Binary inputs for 2-heat/2-cool applications

Installation and 

Operation 

Tracer ZN517 

Unitary Controller 

CNT-SVX12C-EN

Installation and 

Operation 

Tracer ZN517 

Unitary Controller 

CNT-SVX12C-EN 

April 2005

Tracer ZN517 Unitary Controller Installation and Operation 

This guide and the information in it are the property of American Standard Inc. and may not be used or reproduced in whole or in part, 

without the written permission of American Standard Inc. Trane, a business of American Standard, Inc., has a policy of continuous 

product and product data improvement and reserves the right to change design and specification without notice. 

Although Trane has tested the hardware and software described in this guide, no guarantee is offered that the hardware and software 

are error free. 

Trane reserves the right to revise this publication at any time and to make changes to its content without obligation to notify any person 

of such revision or change. 

Trane may have patents or patent applications covering items in this publication. By providing this document, Trane does not imply 

giving license to these patents. 

® 

® 

CNT-SVX12C-EN 

The following are trademarks or registered trademarks of Trane: Trane, Tracer, Tracker, Rover. 

The following are trademarks or registered trademarks of their respective companies or organizations: LonTalk and Neuron 

from Echelon Corporation. 

Printed in the U.S.A. 

© 2005 American Standard Inc. All rights reserved.

NOTICE: 

Warnings and Cautions appear at appropriate sections throughout this manual. Read these carefully: 

�WARNING 

Indicates a potentially hazardous situation, which, if not avoided, could result in death or serious injury. 

�CAUTION 

Indicates a potentially hazardous situation, which, if not avoided, may result in minor or moderate injury. 

It may also be used to alert against unsafe practices. 

CAUTION 

Indicates a situation that may result in equipment damage or property damage. 

The following format and symbol conventions appear at appropriate sections throughout this manual: 

IMPORTANT 

Alerts installer, servicer, or operator to potential actions that could cause the product or system to 

operate improperly but will not likely result in potential for damage. 

Note: 

A note may be used to make the reader aware of useful information, to clarify a point, or to describe 

options or alternatives. 

◆ This symbol precedes a procedure that consists of only a single step. 

CNT-SVX12C-EN

Table of contents 

Chapter 1 Overview and specifications . . . . . . . . . . . . . . . . . . 1 

Product description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

Operating environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

Storage environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Agency listing/compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Factory default temperature setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Additional components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Power transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Zone temperature sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Discharge air temperature sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Damper actuators (optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Chapter 2 Mounting the controller . . . . . . . . . . . . . . . . . . . . . 7 

Location recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Mounting recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Chapter 3 Applications for the 

2-heat/2-cool configuration. . . . . . . . . . . . . . . . . . 9 

Wiring requirements and options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

DIP switch settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Binary outputs for 2-heat/2-cool applications . . . . . . . . . . . . . . . . . . . . 13 

Binary output 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 

Overriding binary outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

Binary inputs for 2-heat/2-cool applications. . . . . . . . . . . . . . . . . . . . . . 14 

BI1: Occupancy or generic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

BI2: Fan status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

CNT-SVX12C-EN i


Analog inputs for 2-heat/2-cool applications . . . . . . . . . . . . . . . . . . . . . 15 

AI1: Universal 4–20 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

AI2: Outdoor air temperature or generic temperature . . . . . . . . . . 17 

DAT: Discharge air temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 

ZN: Zone temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 

SET: Temperature setpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 

Chapter 4 Sequence of operations for the 2-heat/2-cool 

configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

Power-up sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

Cascade zone control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Simplified zone control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Occupancy modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Occupied mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 

Unoccupied mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 

Occupied standby mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 

Occupied bypass mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

Timed override control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

Outdoor air damper operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

Fan operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

Peer-to-peer communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

Economizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

Discharge air tempering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 

Demand control ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 

Unit protection strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 

Filter-maintenance timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 

Fan off delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 

Fan status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 

Chapter 5 Applications for the 4-cool configuration . . . . . . 27 



Binary outputs for 4-cool applications . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

Binary output 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 


Binary inputs for 4-cool applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

BI1: Occupancy or generic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

BI2: Fan status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

Analog inputs for 4-cool applications . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

ii CNT-SVX12C-EN




DAT: Discharge air temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 


SET: Temperature setpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

Chapter 6 Sequence of operations for the 4-cool 

configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 

Power-up sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 

Cascade zone control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 


Occupancy modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 

Occupied mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 

Unoccupied mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 



Timed override control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 

Outdoor air damper operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 

Fan operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 


Economizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 

Discharge air tempering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 


Unit protection strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 


Fan off delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 

Fan status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 

Chapter 7 Applications for the heat pump configuration . . 45 



Binary outputs for heat pump applications . . . . . . . . . . . . . . . . . . . . . . 49 

Binary output 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 


Binary inputs for heat pump applications . . . . . . . . . . . . . . . . . . . . . . . 50 

BI1: Occupancy or generic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 

BI2: Fan status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 

Analog inputs for heat pump applications . . . . . . . . . . . . . . . . . . . . . . . 51 


CNT-SVX12C-EN iii



DAT: Discharge air temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 


SET: Temperature setpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 

Chapter 8 Sequence of operations for the heat pump 

configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 

Power-up sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 

Cascade zone control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 


Occupancy modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 

Occupied mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 

Unoccupied mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 



Timed override control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 

Outdoor air damper operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 

Heating or cooling mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

Fan operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

Compressor operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

Reversing valve operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

Economizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 

Discharge air tempering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 



Unit protection strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 


Fan off delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 

Fan status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 

Chapter 9 PID control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 

What PID loops do. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 

PID calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 

Proportional calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 

Integral calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 

Derivative calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 

Sampling frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 

PID loop action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 

Direct action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 

iv CNT-SVX12C-EN


Reverse action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 

Error deadband . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 

Adjusting error deadband for modulating outputs . . . . . . . . . . . . . 69 

Adjusting error deadband for staged outputs . . . . . . . . . . . . . . . . . 69 

Other PID settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 

Troubleshooting procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 

Tips for specific problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 

Changing the sampling frequency . . . . . . . . . . . . . . . . . . . . . . . . . . 72 

Changing the gains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 

Chapter 10 Status indicators for operation and 

communication. . . . . . . . . . . . . . . . . . . . . . . . . . . 73 

Test button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 

Manual output test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 

Service Pin button. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 

Interpreting LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 

Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 

Diagnostic types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 

Table of diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 

Chapter 11 General wiring information . . . . . . . . . . . . . . . . . . 81 

Input/output terminal wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 

Wiring specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 

HVAC unit electrical circuit wiring . . . . . . . . . . . . . . . . . . . . . . . . . . 82 

AC power wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 

Communication-link wiring and addressing . . . . . . . . . . . . . . . . . . . . . 86 

Chapter 12 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 

Initial troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 

Diagnosing operational problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 

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vi CNT-SVX12C-EN

Chapter 1 

Overview and specifications 

This guide provides installation and configuration information for the 

Tracer ZN517 unitary controller, as well as a description of its operations. 

The overview includes a product description, specifications, and descriptions 

of ancillary products that may be necessary. 

Product description 

The Tracer ZN517 is an application-specific controller that provides 

direct digital, zone temperature control. The controller can operate as a 

stand-alone device or as part of a building automation system (BAS). 

Communication between the controller and a BAS occurs via a LonTalk 

communication link, which is based on the LonTalk ® protocol. 

The controller is designed to be field-installed and is sent from the factory 

configured for a 2-heat/2-cool application. You can change this configuration 

using the DIP switches located on the circuit board. The Tracer 

ZN517 supports the following three configurations: 

• 2-heat/2-cool with optional economizer control 

• 4-cool with optional economizer control 

• Heat pump with optional economizer control 

Features such as discharge air tempering and demand control ventilation 

can be configured using the Rover service tool. 

Note: 

For information about using the Rover service tool, see the 

Rover Operation and Programming guide (EMTX-SVX01B- 

EN). 

Dimensions 

Plastic-cover model dimensions 

For complete dimensional drawing, see Figure 1 on page 3. 

• Height: 5.375 in. (137 mm) 

• Width: 6.875 in. (175 mm) 

• Depth: 2 in. (51 mm) 

CNT-SVX12C-EN 1

Chapter 1 Overview and specifications 

Metal-cover model dimensions 

For complete dimensional drawing, see Figure 2 on page 3. 

• Height: 9.0 in (25 mm) 

• Width: 10.37in. (263 mm) 

• Depth: 2.25 in. (58 mm) 

Clearances 

For wiring, ventilation, and maintenance, provide the following minimum 

clearances for the module: 

Plastic-cover model 

(see Figure 1 on page 3) 

• Front: 4.0 in. (102 mm) 

• Each side: 1.0 in. (25 mm) 

• Top and bottom: 4.0 in. (102 mm) 

Metal-cover model 

(see Figure 2 on page 3) 

• Front: 24.0 in. (610 mm) 

• Each side: 2.0 in. (51 mm) 

• Top and bottom: 1.0 in. (25 mm) 

Power 

The transformer must meet the following minimum requirements for the 

controller and its output devices: 

• 19–30 Vac (24 Vac nominal) 

• 50/60 Hz 

• 9 VA and 12 VA maximum per binary output utilized 

Operating environment 

Operate a Tracer ZN517 unitary controller in an indoor environment that 

meets the following requirements: 

Temperature: From –40°F to 160°F (–40°C to 70°C) 

Relative humidity: From 5–90%, noncondensing 

2 CNT-SVX12C-EN

Figure 1. Plastic-cover model dimensions and clearances 

4 in 

(102 mm) 

5.625 in 

(143 mm) 

1 in. 

(25 mm) 

Figure 2. Metal-cover model dimensions and clearances 

2 in. 

(51 mm) 

9 in. 

(229 mm) 

24 in. 

(610 mm) 

Clearances 

Dimensions 

10.37 in. 

(263 mm) 

width with cover 

Clearances 

Dimensions 

5.375 in (137 mm) 

1 in. 

(25 mm) 

1 in. 

(25 mm) 

2.25 in. 

(58 mm) 

6.31 in. 

(160 mm) 

7 in. 

(178 mm) 

2 in. 

(51 mm) 

1 in. 

(25 mm) 

4 in 

(102 mm) 

1. 875 in. 

(48 mm) 

Operating environment 

4 in 

(102 mm) 6.875 in 

(175 mm) 

6.5 in. 

(165 mm) 

10.25 in. 

(260 mm) 

width without cover 

2 in. (51 mm) 

0.28 in. 

(7 mm) 

9 in. 

(229 mm) 

CNT-SVX12C-EN 3


Storage environment 

If you are storing a Tracer ZN517 unitary controller for a substantial 

amount of time, store it in an indoor environment that meets the 

following requirements: 

Temperature: From –40° to 185°F (–40° to 85°C) 

Relative humidity: From 5–95%, noncondensing 

Agency listing/compliance 

CE—Immunity: EN50082-2:1995 

EN61000-6-2:1999 

CE—Emissions: EN61000-3-2:1995 

EN61000-3-3:1995 

EN50081-1:1992 (CISPR 22) 

EN55011:1998, Class B 

UL and C-UL 916 listed: 

Energy management equipment 

UL 94-5V (UL flammability rating for plenum use) 

FCC Part 15, Class A, CFR 47 

Factory default temperature setpoints 

The Tracer ZN517 unitary controller relies on a number of temperature 

setpoints to control HVAC equipment. Table 1 gives the factory defaults 

for these setpoints, which can all be edited with the Rover service tool or a 

BAS. 

Table 1. Factory default temperature setpoints 

Setpoints 

Factory defaults 

°F (°C) 

Default setpoints 

Occupied cooling 74.0°F (23.3°C) 

Occupied standby cooling 78.0°F (25.6°C) 

Unoccupied cooling 85.0°F (29.4°C) 

Occupied heating 71.0°F (21.7°C) 

Occupied standby heating 67.0°F (19.4°C) 

Unoccupied heating 

Occupied setpoint limits 

60.0°F (15.6°C) 

Cooling setpoint high limit 110.0°F (43.3°C) 

Cooling setpoint low limit 40.0°F (44.4°C) 

4 CNT-SVX12C-EN

Table 1. Factory default temperature setpoints 

Setpoints 

Factory default temperature setpoints 

Factory defaults 

°F (°C) 

Heating setpoint high limit 105.0°F (40.6°C) 

Heating setpoint low limit 

Discharge air limits 

40.0°F (44.4°C) 

High limit 170.6°F (77.0°C) 

Low limit 37.4°F (3.0°C) 

Control point high limit 150.8°F (66.0°C) 

Control point low limit 

Outdoor air damper setup 

44.6°F (7.0°C) 

Economizer enable temperature 53.6°F (12.0°C) 

CNT-SVX12C-EN 5


Additional components 

The following components are required for proper equipment operation. 

They are not included with the Tracer ZN517 unitary controller. Additional 

components may also be required besides those described in this 

section, depending on your application. 

Power transformer 

A transformer providing 24 Vac is required to power the Tracer ZN517 

unitary controller and associated output relays and valve and damper 

actuators (see “AC power wiring” on page 85). 

Zone temperature sensors 

Table 2 shows some of the Trane zone temperature sensors that are supported 

by the Tracer ZN517 unitary controller. Contact your Trane sales 

office for information about other compatible zone sensors. 

Table 2. Trane zone temperature sensor options 

BAS order 

number 

Setpoint 

thumbwheel 

Discharge air temperature sensors 

Discharge air temperature sensors must be Trane 10 kΩ (at 25°C) thermistors. 

The discharge air temperature (DAT) input may use a sealed 

temperature sensor (part number 4190 1100) or a duct/immersion temperature 

sensor (part number 4190 1103). 

Damper actuators (optional) 

Actuators cannot exceed 12 VA draw at 24 Vac. Use actuators with on/off 

action and spring return (to normally open or closed position), based on 

the desired default position. 

6 CNT-SVX12C-EN 

Zone 

Temperature 

sensor 

Timed override 

buttons 

On Cancel 

Comm 

jack 

4190 1086 x x x 

4190 1087 x 

4190 1088 x x x x 

4190 1089 x x 

4190 1090 x x x x x 

4190 1094 x x x 

4190 7015 

(stainless 

steel wall 

plate) 

x

Chapter 2 

Mounting the controller 

This chapter gives recommendations and requirements for mounting the 

Tracer ZN517 unitary controller. 

Location recommendations 

For rooftop and heat pump applications, the controller can be mounted 

inside the unit or at a convenient location inside the building. Trane 

recommends locating the Tracer ZN517 unitary controller: 

• Near the controlled piece of equipment to reduce wiring costs 

• Where it is easily accessible for service personnel 

• Where public access is restricted to minimize the possibility of tampering 

or vandalism 

CNT-SVX12C-EN 7

Chapter 2 Mounting the controller 

Mounting recommendations 

Mounting recommendations are as follows: 

IMPORTANT 

Mount the Tracer ZN517 unitary controller with the cover on to avoid 

the possibility of damaging the circuit board during installation. 

• Mount the controller in any direction, other than with the front of the 

cover facing downward. 

• Mount using the two 3 / 16 in. (4.8 mm) radius mounting holes provided 

(see Figure 3). Mounting fasteners are not included. 

• Attach the controller securely so it can withstand vibrations of associated 

HVAC equipment. 

• When the controller is mounted in a small enclosed compartment, 

complete all wiring connections before securing the controller in the 

compartment. 

Figure 3. Mounting the Tracer ZN517 unitary controller 

8 CNT-SVX12C-EN

Chapter 3 

Applications for the 

2-heat/2-cool configuration 

This chapter provides information for wiring input and output terminals 

and setting DIP switches for typical 2-heat/2-cool applications. The function 

of inputs and outputs is also defined for these applications. 

The types of 2-heat/2-cool applications supported by the Tracer ZN517 

unitary controller are: 

• Rooftop units with or without economizers 

• Split systems with or without economizers 

CNT-SVX12C-EN 9

Chapter 3 Applications for the 2-heat/2-cool configuration 

Wiring requirements and options 

Table 3 shows required controller inputs for minimal proper operation of 

all 2-heat/2-cool applications. 

Table 3. Required controller inputs for all 2-heat/2-cool applications 

Function Input source 

For more information, 

see: 

24 Vac power Terminals: GND, 24 V “AC power wiring” on 

page 85 

Zone temperature Terminals: ZN, GND 

or communicated 

“ZN: Zone temperature” 

on page 18 

Table 4 shows optional controller inputs and outputs for specific 

applications. 

Table 4. Optional controller inputs and outputs for specific applications 

Application Input/Output 

Economizing Input: 

DAT (discharge air temperature) 

Input: 

AI2 (outdoor air temperature) 

Outputs: 

24 V (24 Vac common) 

OPN (binary output) 

CLS (binary output) 

Discharge air 

tempering* 

Demand control 

ventilation* 


see: 

“Economizing” on 

page 23 

Input: DAT “Discharge air tempering” 

on page 24 

Input: 

AI1 (CO 2 sensor) 

“Demand control 

ventilation” on 

page 24 

Cascade control Input: DAT “Cascade zone control” 

on page 20 

* In order to use this function, the economizing function must be enabled. 

Figure 4 on page 11 shows a wiring diagram for the Tracer ZN517 that 

includes all required and all optional components for 2-heat/2-cool applications. 

10 CNT-SVX12C-EN

24 Vac 

H 

N 

LonTalk 

In 

Out 

*Terminals Rc and Rh are provided as 

inputs for 24 Vac power from the controlled 

device. If the device has a separate 

heating and cooling units, use Rh 

for heat and Rc for cooling. If combined, 

use only Rc (see “HVAC unit 

electrical circuit wiring” on page 82). 


Figure 4. Wiring diagram for 2-heat/2-cool applications 

Common 

GND 24V GND 24V GND 24V OPN CLS 

AC POWER 

AC OUT 

ECONOMIZER 

Rc Rh G 1 2 3 4 5NO 5COM 

HVAC UNIT 

COMM5 BINARY INPUTS 

ANALOG INPUTS 

ZONE SENSOR 

SERVICE 

LED PIN A B A B -BI1- -BI2- GND +20 AI1 -AI2- -DAT- ZN GND SET 

COMM5 

LED 

Occupancy 

or generic 

(optional) 

Tri-state 

modulating 

economizer 

(optional) 

Dry contacts 

only 

+ _ 

GND 

CNT-SVX12C-EN 11 

Power* 

Typical 3-wire 

sensor 

(optional) 

Fan 

R G Y1 Y2 W1 W2 

(optional) 

Fan status 

(default: 

normally closed 

closed = no flow 

open = flow) 

or generic 

Compressor 1 contactor 


Heat stage 1 

5NC 

BINARY OUTPUT 

Discharge air 

temperature 

Outdoor air 

temperature 

(optional) 

Heat stage 2 

Generic binary output (optional) 

STATUS 

LED 

LonTalk 

1 

2 

3 

4 

5 

On 

Cancel


DIP switch settings 

Set the DIP switches on the circuit board for the 2-heat/2-cool configuration. 

The correct settings are shown in Figure 5. 

Figure 5. DIP switch settings for the 2-heat/2-cool configuration 

ON DIP 

1 2 3 4 

ON DIP 2-heat/2-cool 

without economizer 

1 2 3 4 

ON DIP 

1 2 3 4 

2-heat/2-cool with 

economizer 

12 CNT-SVX12C-EN

Binary outputs for 2-heat/2-cool applications 

Binary outputs for 2-heat/2-cool 

applications 

This configuration supports rooftop units and split systems applications 

that have the following components: 

• Economizer 

• Supply fan 

• Cool 1 

• Cool 2 

• Heat 1 

• Heat 2 

• Exhaust 

The Tracer ZN517 controller has eight binary outputs. Each binary output 

is a relay with a rating of 12 VA. Table 5 describes the function of 

each output for 2-heat/2-cool applications. 

Table 5. Binary outputs for 2-heat/2-cool applications 

Binary output terminal label Function 

OPN Economizer, drive open 

CLS Economizer, drive closed 

G Supply fan 

1 (Y1) Cool stage 1 


3 (W1) Heat stage 1 

4 (W2) Heat stage 2 

5NO/5COM/5NC (binary output 5) Exhaust fan/occupancy/generic 

Binary output 5 

Use the Rover service tool to configure binary output 5 (5NO/5COM/5NC) 

in one of the following ways. It is the only output that can be configured 

as a generic binary output. 

• Not used. 

• Exhaust fan: Will energize when the economizer outside air damper 

position is greater than the user-defined control point. 

• Occupancy: Will energize when the Tracer ZN517 is in the occupied 

mode. 

• Generic: Can be monitored only by a BAS and has no direct effect on 

Tracer ZN517 operation. 

CNT-SVX12C-EN 13


Overriding binary outputs 

Use the manual output test to manually control the outputs in a defined 

sequence. For more information about the manual output test, see “Manual 

output test” on page 74. 

Binary inputs for 2-heat/2-cool 


The Tracer ZN517 unitary controller has two binary inputs. Each binary 

input associates an input signal of 0 Vac with open contacts and 24 Vac 

with closed contacts. Table 6 gives the function of each binary input for 

2 heat/2 cool applications. Each function is explained in the succeeding 

paragraphs. For an explanation of the diagnostics generated by each 

binary input, see “Table of diagnostics” on page 79. For more information 

about how the controller operates, see Chapter 4, “Sequence of operations 

for the 2-heat/2-cool configuration”.” 

Table 6. Binary inputs for 2-heat/2-cool applications 

Binary input 

terminal label 

BI1 Occupancy or generic 

BI2 Fan status 

BI1: Occupancy or generic 

The function of the occupancy input is to save energy by increasing the 

range of zone setpoints when the zone is unoccupied. BI1 is used for two 

occupancy-related functions. For stand-alone controllers, this binary 

input can be hard-wired to a binary switch, clock, or occupancy sensor to 

determine the occupancy mode—either occupied or unoccupied. For controllers 

receiving a BAS-communicated occupancy request, the function of 

BI1 is to change the mode from occupied to occupied standby. (For more 

information on occupancy-related functions, see “Occupancy modes” on 

page 20.) An occupancy sensor with a binary output may be used. 

BI1 is the only input that can be configured as a generic binary input. 

When configured as a generic binary input, it can be monitored only by a 

BAS, and has no direct effect on Tracer ZN517 operation. 

BI2: Fan status 

Function 

The fan status input provides feedback to the controller regarding the 

fan’s operating status. If BI2 is wired to a fan status switch and the input 

indicates that the fan is not operating when the controller has the fan 

controlled to on, the controller will generate a Local Fan Switch Failure 

diagnostic. (For more information, see “Fan status” on page 25.) 

14 CNT-SVX12C-EN

Analog inputs for 2-heat/2-cool applications 

Analog inputs for 2-heat/2-cool 


The Tracer ZN517 controller has five analog inputs. Table 7 describes the 

function of each input for 2-heat/2-cool applications. Each function is 

explained in the succeeding paragraphs. For an explanation of the diagnostics 

generated by each analog input, see “Table of diagnostics” on 

page 79. For more information about how the controller operates, see 

Chapter 4, “Sequence of operations for the 2-heat/2-cool configuration”. 

Table 7. Analog inputs for 2-heat/2-cool applications 

Analog input 


AI1: Universal 4–20 mA 

Function 

AI1 Universal analog input 

AI2 Outdoor air temperature 

DAT Discharge air temperature 

ZN Zone temperature (required) 

SET Temperature setpoint 

Note: 

Use a GND terminal as the common ground for all zone sensor 

analog inputs. See Figure 4 on page 11. 

The AI1 analog input can be configured in one of the three ways shown in 

Table 8. 

Table 8. AI1 configuration options and associated measurement ranges 

Configuration Measurement range 

Generic 4–20 mA input 0–100% 

(4 mA=0%; 20 mA=100%) 

CO2 measurement 0–2000 ppm 

(4 mA=0 ppm; 20 mA=2000 ppm) 

Relative humidity (RH) measurement 0–100% 

(4 mA=0% RH; 20 mA=100% RH) 

If this input is not needed for an application, configure it as Not Used. 

This disables the generation of diagnostics. 

Note: 

AI1 is polarity sensitive. 

For the generic input configuration, a 4–20 mA sensor must be hardwired 

to the AI1 terminal. (Wiring is dependent on the specific applica- 

CNT-SVX12C-EN 15


tion.) The sensor communicates a value of 0–100% to the BAS. This configuration 

has no direct effect on Tracer ZN517 operation. 

For the CO2 measurement configuration, a 4–20 mA sensor must be hardwired 

to the AI1 terminal as shown in Figure 6. The sensor will transmit 

a 0–2000 ppm value to the BAS. This configuration has no direct effect on 

Tracer ZN517 operation. If a valid value is established and then is no 

longer present, the controller generates a CO2 Sensor Failure diagnostic. 

Figure 6. AI1 terminal wiring: CO 2 measurement 

CO 2 sensor 

(Trane part number: 

4190 4100 or 4190 4101) 

Tracer ZN517 

24 Vac 

For the RH measurement configuration, a hard-wired 4–20 mA zone 

humidity sensor (see Figure 7) must provide a value to the controller. If a 

valid hard-wired or communicated relative humidity value is established 

and then is no longer present, the controller generates an RH Sensor Failure 

diagnostic and disables the dehumidification function. The RH sensor 

is used only to provide a valid humidity reading to a BAS; it does not 

affect the operation of the Tracer ZN517. 

Figure 7. AI1 terminal wiring: RH measurement 


{{ 

24 Vac 

+ – 

GND +20 AI1 

GND Out 

GND +20 AI1 Tracer ZN517 

RH sensor 

Figure Note: 

The +20 terminal provides 20 ±2 Vdc that is used to power a Trane RH sensor (part 

numbers 4190 1109, 4190 7011, 4190 7012, 4190 7014).

Analog inputs for 2-heat/2-cool applications 

AI2: Outdoor air temperature or generic temperature 

The AI2 analog input can functions as either: 

• An outdoor air temperature input 

• A generic temperature input 

If AI2 is configured as the local (hard-wired) outdoor air temperature 

input, the controller receives the temperature as a resistance signal from 

a 10 kΩ thermistor wired to analog input AI2. An outdoor air temperature 

value communicated by means of a LonTalk link can also be used for 

controllers operating on a BAS. If both hard-wired and communicated 

outdoor air temperature values are present, the controller uses the communicated 

value. 

If you set DIP switch 3 to ON for economizing (see “DIP switch settings” 

on page 12), you automatically configure AI2 as an outdoor air temperature 

input. Economizing (free cooling) is a function whereby outdoor air is 

used as a source of cooling before hydronic or DX cooling is used. The 

Tracer ZN517 uses the outdoor air temperature value to determine 

whether economizing is feasible. Economizing is not possible without a 

valid outdoor air temperature. (For more information, see “Economizing” 

on page 23.) 

If AI2 is configured as a generic temperature input, it can be monitored 

by a BAS. The controller receives the temperature as a resistance signal 

from a 10 kΩ thermistor wired to analog input AI2. The generic temperature 

input can be used with any Trane 10 kΩ thermistor. The thermistor 

can be placed in any location and has no effect on the operation of the controller. 

If you set DIP switch 3 to OFF (see “DIP switch settings” on 

page 12), you automatically configure AI2 as a generic temperature input. 

Note: 

AI2 is not polarity sensitive; you can connect either terminal to 

either sensor lead. 

DAT: Discharge air temperature 

The DAT analog input functions as the local discharge air temperature 

input. The controller receives the temperature as a resistance signal from 

a 10 kΩ thermistor wired to analog input DAT. The thermistor is typically 

located downstream from all unit heating and cooling coils at the unit discharge 

area. 

Trane recommends the use of a discharge air temperature sensor to utilize 

the cascade control function (see “Cascade zone control” on page 20). 

Cascade control is a more accurate method of temperature control. If no 

discharge air temperature sensor is used, the controller will default to 

control based solely on the zone temperature (see “Simplified zone control” 

on page 20). 

Note: 

DAT is not polarity sensitive; you can connect either terminal 

to either sensor lead. 

CNT-SVX12C-EN 17


ZN: Zone temperature 

The ZN analog input functions as the local (hard-wired) zone temperature 


a 10 kΩ thermistor in a standard Trane zone sensor wired to analog input 

ZN. A communicated zone temperature value via the LonTalk communications 

link can also be used for controllers operating on a BAS. When 

both a hard-wired and communicated zone temperature value is present, 

the controller uses the communicated value. If neither a hard-wired nor a 

communicated zone temperature value is present, the controller generates 

a Space Temperature Failure diagnostic. 

The ZN analog input is also used to communicate timed override requests 

and cancel requests to the controller for applications utilizing a Trane 

zone sensor with the ON and CANCEL button option. 

SET: Temperature setpoint 

The SET analog input functions as the local (hard-wired) temperature 

setpoint input for applications utilizing a Trane zone sensor with a temperature 

setpoint thumbwheel. Use the Rover service tool or a BAS to 

enable or disable the local setpoint input. A communicated setpoint value 

via the LonTalk communications link can also be used for controllers 

operating on a BAS. If both a hard-wired and a communicated setpoint 

value are present, the controller uses the communicated value. If neither 

a hard-wired nor a communicated setpoint value is present, the controller 

uses the stored default setpoints (configurable using the Rover service 

tool or a BAS). If a valid hard-wired or communicated setpoint value is 

established and then is no longer present, the controller generates a Local 

Space Setpoint Failure diagnostic. 

18 CNT-SVX12C-EN

Chapter 4 

Sequence of operations for the 


A Tracer ZN517 unitary controller configured to control a 2-heat/2-cool 

unit will operate to maintain the zone temperature setpoint. This chapter 

discusses many of the operational sequences the controller uses to accomplish 

this goal. 

Power-up sequence 

When 24 Vac power is initially applied to the Tracer ZN517 unitary controller, 

the following sequence occurs: 

1. The Status (green) LED goes on. 

2. All outputs are controlled off. 

3. The controller reads all input local values to determine initial values. 

4. The power-up control wait function begins automatically if the configured 

power-up control wait time is greater than zero. When this function 

is enabled, the controller waits for the configured amount of time 

(from 10 to 120 seconds) to allow a communicated occupancy request 

to arrive. If a communicated occupancy request arrives, normal operation 

can begin. If a communicated occupancy request does not arrive, 

the controller assumes stand-alone operation. 

5. The Status LED goes off. 

6. The wait timer expires. 

7. The Status LED goes on. 

8. If a hard-wired zone-temperature value is not detected, the controller 

begins to wait for a communicated value. (This can take several minutes 

[15-minute default] and occurs concurrently with the remainder 

of the power-up sequence.) If a communicated zone-temperature 

value arrives, normal operation can begin when the power-up 

sequence has concluded. If a communicated zone-temperature value 

does not arrive, the binary outputs remain off and a Space Temperature 

Failure diagnostic is generated (normal operation cannot begin 

without a valid zone temperature value). 

9. Normal operation begins assuming no diagnostics have been generated. 

CNT-SVX12C-EN 19

Chapter 4 Sequence of operations for the 2-heat/2-cool configuration 

Cascade zone control 

Cascade zone control maintains zone temperature by controlling the discharge 

air temperature to control the zone temperature. The controller 

uses the difference between the measured zone temperature and the 

active zone temperature setpoint to produce a discharge air temperature 

setpoint. The controller compares the discharge air temperature setpoint 

with the discharge air temperature and calculates a unit heating/cooling 

capacity accordingly (see Figure 8). The end devices (outdoor air damper, 

valves, etc.) operate in sequence based on the unit heating/cooling capacity 

(0–100%). 

Figure 8. Cascade zone control 

Active zone 

temperature 

setpoint 

Difference 

Measured 

zone 

temperature 

If the discharge air temperature falls below the Discharge Air Control 

Point Low Limit (configurable using the Rover service tool) and cooling 

capacity is at a minimum, available heating capacity will be used to raise 

the discharge air temperature to the low limit (see “Discharge air tempering” 

on page 24). 

Simplified zone control 

Calculated 

discharge air 

temperature 

setpoint 

In the absence of a discharge air temperature sensor, the controller uses 

simplified zone control to maintain the zone temperature. In the unoccupied 

mode, the controller maintains the zone temperature by calculating 

the required heating or cooling capacity (0–100%) according to the measured 

zone temperature and the active zone temperature setpoint. The 

active zone temperature setpoint is determined by the current operating 

modes, which include occupancy and heat/cool modes. 

Occupancy modes 

Difference 

Measured 

discharge air 

temperature 

Occupancy modes can be controlled by any of the following: 

Calculated unit 

heating/cooling 

capacity 

• The state of the local (hard-wired) occupancy binary input BI1 (see 

“BI1: Occupancy or generic” on page 50) 

• A timed override request from a Trane zone sensor (see “Timed override 

control” on page 22) 

20 CNT-SVX12C-EN


• A communicated signal from a peer device (see “Peer-to-peer communication” 

on page 23) 

• A communicated signal from a BAS 

A communicated request, either from a BAS or a peer controller, takes 

precedence over local requests. If a communicated occupancy request has 

been established and is no longer present, the controller reverts to the 

default (occupied) occupancy mode after 15 minutes (if no hard-wired 

occupancy request exists). The Tracer ZN517 has the following occupancy 

mode options: 

• Occupied 

• Unoccupied 

• Occupied standby 

• Occupied bypass 

Occupied mode 

In occupied mode, the controller maintains the zone temperature based 

on the occupied heating or cooling setpoints. The controller uses the occupied 

mode as a default when other modes of occupancy request are not 

present. The fan runs as configured (continuous or cycling). The outdoor 

air damper closes when the fan is off. The temperature setpoints can be 

local (hard-wired), communicated, or stored default values (configurable 

using the Rover service tool or a BAS). 

Unoccupied mode 

In unoccupied mode, the controller attempts to maintain the zone temperature 

based on the unoccupied heating or cooling setpoint. The fan cycles 

between high speed and off. The outdoor air damper remains closed. The 

controller always uses the stored default setpoint values (configurable 

using the Rover service tool or a BAS), regardless of the presence of a 

hard-wired or communicated setpoint value. 

Occupied standby mode 

The controller is placed in occupied standby mode only when a communicated 

occupied request is combined with an unoccupied request from 

occupancy binary input BI1. In occupied standby mode, the controller 

maintains the zone temperature based on the occupied standby heating 

or cooling setpoints. Because the occupied standby setpoints are typically 

spread 2°F (1.1°C) in either direction and the outdoor air damper is 

closed, this mode reduces the demand for heating and cooling the space. 

The fan runs as configured (continuous or cycling) for occupied mode. The 


using the Rover service tool or a BAS), regardless of hard-wired or communicated 

setpoint values. 

CNT-SVX12C-EN 21


Occupied bypass mode 

The controller is placed in occupied bypass mode when the controller is 

operating in the unoccupied mode and either the timed override ON button 

on the Trane zone sensor is pressed or the controller receives a communicated 

occupied bypass signal from a BAS. In occupied bypass mode, 

the controller maintains the zone temperature based on the occupied 

heating or cooling setpoints. The fan runs as configured (continuous or 

cycling). The outdoor air damper closes when the fan is off. The controller 

will remain in occupied bypass mode until either the CANCEL button is 

pressed on the Trane zone sensor or the occupied bypass time (configurable 

using the Rover service tool or a BAS) expires. The temperature 

setpoints can be local (hard-wired), communicated, or stored default values 

(configurable using the Rover service tool or a BAS). 

Timed override control 

If the zone sensor has a timed override option (ON/CANCEL buttons), 

pushing the ON button momentarily shorts the zone temperature signal 

to the controller. This short is interpreted as a timed override on request. 

A timed override on request changes the occupancy mode from unoccupied 

mode to occupied bypass mode. In occupied bypass mode, the controller 

controls the zone temperature based on the occupied heating or 

cooling setpoints. The occupied bypass time, which resides in the Tracer 

ZN517 and defines the duration of the override, is configurable (using the 

Rover service tool or a BAS) from 0 to 240 minutes (default value is 

120 minutes). When the occupied bypass time expires, the unit changes 

from occupied bypass mode to unoccupied mode. Pushing the CANCEL 

button momentarily sends a fixed resistance of 1.5 kΩ to the ZN analog 

input of the controller, which is interpreted as a timed override cancel 

request. A timed override cancel request will end the timed override 

before the occupied bypass time has expired and will transition the unit 

from occupied bypass mode to unoccupied mode. 

If the controller is in any mode other than unoccupied when the ON button 

is pressed, the controller still starts the occupied bypass timer without 

changing the mode to occupied bypass. If the controller is placed in 

unoccupied mode before the occupied bypass timer expires, the controller 

will be placed in occupied bypass mode and remain in that mode until 

either the CANCEL button is pressed on the Trane zone sensor or the 

occupied bypass time expires. 

Outdoor air damper operation 

The Tracer ZN517 does not support a two-position outdoor air damper 

actuator. However, a modulating, triac, 3-wire floating point actuator 

with spring return can be used for two-position control. Two-position control 

can function only when an outdoor air temperature (either hardwired 

or communicated) does not exist, and by setting the damper minimum 

position (using the Rover service tool) to the desired value. To con- 

22 CNT-SVX12C-EN

Fan operation 

trol an air damper actuator for two-position control, configure the Tracer 

ZN517 for economizing (economizing will not function). 

Fan operation 

The Tracer ZN517 can be configured to run continuously at a single speed 

or to cycle on and off automatically. If configured for continuous operation, 

the fan runs continuously during the occupied, occupied standby, 

and occupied bypass modes. If configured for cycling operation, the fan 

will cycle if the temperature is away from setpoint during the occupied, 

occupied standby, and occupied bypass modes. During the unoccupied 

mode, the fan cycles regardless of the fan configuration. 

Peer-to-peer communication 

Tracer ZN517 unitary controllers have the ability to share data with 

other LonTalk-based controllers. Multiple controllers can be bound as 

peers, using the Rover service tool, to share: 

• Setpoint 

• Zone temperature 

• Heating/cooling mode 

• Fan status 

• Unit capacity control 

Shared data is communicated from one controller to any other controller 

that is bound to it as a peer. Applications having more than one unit serving 

a single zone can benefit by using this feature; it allows multiple units 

to share a single zone temperature sensor and prevents multiple units 

from simultaneously heating and cooling. 

Economizing 

Economizing (also referred to as “free cooling”) uses outside air for cooling. 

The Tracer ZN517 provides two triac (3-wire floating point) outputs 

to control the damper actuator. One output opens the actuator; the other 

closes it. The controller also provides analog inputs for both a discharge 

air temperature sensor and an outside air temperature sensor. While 

economizing is enabled, the controller uses a discharge air temperature 

(DAT) control loop to maintain proper temperature control. The controller 

opens the outside air damper, turns on the fan, and attempts to maintain 

a user-defined discharge air temperature. If the outside air is unsuitable 

for economizer operation, the outside air damper will close and normal 

operation (DX cooling) will be activated. Economizing plus DX cooling is 

initiated only when economizing alone cannot meet the zone’s cooling 

requirements. 

To enable this function, set DIP switch 3 to ON (see “DIP switch settings” 

on page 12). 

CNT-SVX12C-EN 23


Discharge air tempering 

Discharge air tempering (also called supply air tempering) prevents occupant 

discomfort caused by cold outside air being brought into a space 

through the outside air damper. This is an important feature in cold climates 

because the outside air damper is never fully closed for ventilation 

purposes. Discharge air tempering starts when: 

• The controller is in heating mode. 

• The space is otherwise satisfied (no heating or cooling required). 

• Ventilation air is passing through the unit 

• The discharge air temperature falls 10°F (5.6°C) below the occupied 

heating setpoint. 

Tempering stops when the occupied heating setpoint is exceeded. To 

enable this function, use the Rover service tool to select Supply Air Tempering 

Enabled. 

Demand control ventilation 

The Tracer ZN517 unitary controller modulates the outside air damper 

position in direct response to the CO2 level, regulating the amount of outdoor 

air allowed to enter. This function is referred to as demand control 

ventilation. Demand control ventilation requires that the two triac (3wire 

floating point) outputs be used to control the damper actuator. The 

minimum damper position will increase as CO2 levels rise above 

500 ppm. The function executes with a 3-minute loop frequency to allow 

time for the sensor to respond. 

To enable this function, use the Rover service tool to configure the Tracer 

ZN517 as follows: 

• Configure AI1 as a carbon dioxide sensor 

• Enter a minimum CO2 level (Control Point) 

(factory default: 500 ppm). 

• Enter a maximum CO2 threshold (Threshold) 


When the CO2 level reaches the threshold, the minimum position is 

100% open. 

Unit protection strategies 

The following strategies are initiated when specific conditions exist in 

order to protect the unit or building from damage: 

• Filter maintenance timer 

• Fan off delay 


24 CNT-SVX12C-EN

Filter-maintenance timer 


The filter-maintenance timer tracks the amount of time (in hours) that 

the fan is enabled. The Maintenance Required Timer Setpoint (Maint Req 

Time Setpoint), configured with the Rover service tool, is used to set the 

amount of time until maintenance (typically, a filter change) is needed. If 

the setpoint is configured to zero, the filter-maintenance timer is disabled. 

The controller compares the fan-run time to Maintenance Required Timer 

Setpoint. Once the setpoint is reached, the controller generates a Maintenance 

Required diagnostic. When the diagnostic is cleared, the controller 

resets the filter-maintenance timer to zero, and the timer begins accumulating 

fan-run time again. 

Fan off delay 

The fan stays on for an additional 30 seconds (adjustable with the Rover 

service tool) to allow the residual cooling or heating energy to be circulated 

through the system. 

Fan status 

The controller monitors fan status to protect equipment from overheating. 

If fan or airflow is not detected for 30 seconds when needed, the 

equipment shuts down. 

CNT-SVX12C-EN 25


26 CNT-SVX12C-EN

Chapter 5 

Applications for the 4-cool 

configuration 


and setting DIP switches for typical 4-cool applications. The function of 

inputs and outputs is also defined for these applications. 

The types of 4-cool applications supported by the Tracer ZN517 unitary 

controller are rooftop units with or without economizers. 

CNT-SVX12C-EN 27

Chapter 5 Applications for the 4-cool configuration 



all 4-cool applications. 

Table 9. Required controller inputs for all 4-cool applications 



see: 


page 85 




on page 36 



Table 10. Optional controller inputs and outputs for specific 





Input: 


Outputs: 




Discharge air 

tempering* 


ventilation* 


see: 


page 23 


on page 24 

Input: 




page 24 


on page 20 


Figure 9 on page 29 show typical applications that include all required 

and all optional components for 4-cool applications. 

28 CNT-SVX12C-EN

24 Vac 

H 

N 

LonTalk 

In 

Out 

Figure 9. Wiring diagram for 4-cool applications 


AC POWER 

AC OUT 








Common 

ECONOMIZER 


HVAC UNIT 


ANALOG INPUTS 

ZONE SENSOR 

SERVICE 


COMM5 

LED 

Occupancy 

or generic 

(optional) 

Tri-state 

modulating 

economizer 

(optional) 

Dry contacts 

only 

+ _ 

GND 



Power* 

Fan 

R G Y1 Y2 Y3 Y4 


sensor 

(optional) 

Fan status or 

generic 

(optional) 




5NC 

BINARY OUTPUT 

Discharge air 

temperature 

Outdoor air 

temperature 

(optional) 



STATUS 

LED 

LonTalk 

1 

2 

3 

4 

5 

On 

Cancel



Set the DIP switches on the circuit board for the 4-cool configuration. The 

correct settings are shown in Figure 10. 

Figure 10. DIP switch settings for the 4-cool configuration 

ON DIP 

1 2 3 4 

ON DIP 

1 2 3 4 

ON DIP 

1 2 3 4 

4-cool without 

economizer 

4-cool with 

economizer 

30 CNT-SVX12C-EN

Binary outputs for 4-cool applications 

Binary outputs for 4-cool applications 

This configuration supports rooftop unit applications that have the following 

components: 



• Cool 1 

• Cool 2 

• Cool 3 

• Cool 4 

• Exhaust fan 

The Tracer ZN517 controller has seven binary outputs. Each binary output 


each output for 4-cool applications. 

Table 11. Binary outputs for 4-cool applications 




G Supply fan 





5NO/5COM/5NC (binary output 5) Exhaust fan/generic/occupancy 





• Not used. 




mode. 







CNT-SVX12C-EN 31


Binary inputs for 4-cool applications 




4-cool applications. Each function is explained in the succeeding paragraphs. 

For an explanation of the diagnostics generated by each binary 

input, see “Table of diagnostics” on page 79. For more information about 

how the controller operates, see Chapter 6, “Sequence of operations for 

the 4-cool configuration”.” 

Table 12. Binary inputs for 4-cool applications 














page 38.) 





Function 






32 CNT-SVX12C-EN

Analog inputs for 4-cool applications 


The Tracer ZN517 controller has five analog inputs. Table 13 describes 

the function of each input for 4-cool applications. Each function is 




Chapter 6, “Sequence of operations for the 4-cool configuration”. 

Table 13. Analog inputs for 4-cool applications 

Analog input 



Function 






Note: 




Table 14. 

Table 14. AI1 configuration options and associated measurement 

ranges 



(4 mA=0%; 20 mA=100%) 


(4 mA=0 ppm; 20 mA=2000 ppm) 


(4 mA=0% RH; 20 mA=100% RH) 



Note: 



to the AI1 terminal. (Wiring is dependent on the specific application.) 

The sensor communicates a value of 0–100% to the BAS. This configuration 


CNT-SVX12C-EN 33


For the CO 2 measurement configuration, a 4–20 mA sensor must be hardwired 

to the AI1 terminal as shown in Figure 11 on page 34. The sensor 

will transmit a 0–2000 ppm value to the BAS. This configuration has no 

direct effect on Tracer ZN517 operation. If a valid value is established 

and then is no longer present, the controller generates a CO 2 Sensor Failure 

diagnostic. 


CO 2 sensor 


4190 4100 or 4190 4101) 

Tracer ZN517 

24 Vac 


humidity sensor (see Figure 12) must provide a value to the controller. If 

a valid hard-wired or communicated relative humidity value is established 

and then is no longer present, the controller generates an RH Sensor 

Failure diagnostic and disables the dehumidification function. The 

RH sensor is used only to provide a valid humidity reading to a BAS; it 

does not affect the operation of the Tracer ZN517. 



{{ 

24 Vac 

GND +20 AI1 

+ – 

GND +20 AI1 

GND Out 

Tracer ZN517 

RH sensor 

Figure Note: 


numbers 4190 1109, 4190 7011, 4190 7012, 4190 7014).



The AI2 analog input can function as either: 









value. 








on page 41.) 








Note: 








area. 






on page 38). 

Note: 



CNT-SVX12C-EN 35




























36 CNT-SVX12C-EN

Chapter 6 

Sequence of operations for 

the 4-cool configuration 

A Tracer ZN517 unitary controller configured to control a 4-cool unit will 

operate to maintain the zone temperature setpoint. This chapter discusses 

many of the operational sequences the controller uses to accomplish 

this goal. 



























CNT-SVX12C-EN 37

Chapter 6 Sequence of operations for the 4-cool configuration 










(0–100%). 


Active zone 

temperature 

setpoint 

Difference 

Measured 

zone 

temperature 





on page 42). 


Calculated 

discharge air 

temperature 

setpoint 









Difference 

Measured 

discharge air 

temperature 




capacity 





38 CNT-SVX12C-EN



on page 41) 







mode options: 

• Occupied 




Occupied mode 




present. The fan runs as configured (continuous or cycling). The outdoor 

air damper closes when the fan is off. The temperature setpoints can be 

local (hard-wired), communicated, or stored default values (configurable 

using the Rover service tool or a BAS). 


In unoccupied mode, the controller attempts to maintain the zone temperature 


between high speed and off. The outdoor air damper remains closed. The 












The fan runs as configured (continuous or cycling) for occupied mode. 

CNT-SVX12C-EN 39









cycling). The outdoor air damper closes when the fan is off. The controller 

will remain in occupied bypass mode until either the CANCEL button is 

pressed on the Trane zone sensor or the occupied bypass time (configurable 

using the Rover service tool or a BAS) expires. The temperature 

setpoints can be local (hard-wired), communicated, or stored default values 

(configurable using the Rover service tool or a BAS). 










Rover service tool or a BAS) from 0 to 240 minutes (default value is 120 

minutes). When the occupied bypass time expires, the unit changes from 

occupied bypass mode to unoccupied mode. Pushing the CANCEL button 

momentarily sends a fixed resistance of 1.5 kΩ to the ZN analog input of 

the controller, which is interpreted as a timed override cancel request. A 

timed override cancel request will end the timed override before the occupied 

bypass time has expired and will transition the unit from occupied 

bypass mode to unoccupied mode. 















40 CNT-SVX12C-EN

Fan operation 



Fan operation 












• Setpoint 










Economizing 













requirements. 


on page 30). 

CNT-SVX12C-EN 41















Enabled. 



position in direct response to the CO2 level, regulating the amount of outdoor 


ventilation. Demand control ventilation requires that the two triac (3wire 

floating point) outputs be used to control the damper actuator. The 


500 ppm. The function executes with a 3-minute loop time to allow time 

for the sensor to respond. 









100% open. 




• Filter maintenance timer 



42 CNT-SVX12C-EN













Fan off delay 


service tool) to allow the residual cooling energy to be circulated through 

the system. 

Fan status 




CNT-SVX12C-EN 43


44 CNT-SVX12C-EN

Chapter 7 

Applications for the heat 

pump configuration 


and setting DIP switches for typical heat pump applications. The function 

of inputs and outputs is also defined for these applications. 

The types of heat pump applications supported by the Tracer ZN517 unitary 

controller are heat pumps with: 

• One or two compressors with reversing valves 

• Optional auxiliary heat control 

• Optional economizer control 

CNT-SVX12C-EN 45

Chapter 7 Applications for the heat pump configuration 



all heat pump applications. 

Table 15. Required controller inputs for proper operation 



see: 


page 85 




on page 54 



Table 16. Optional controller inputs and outputs for specific 





Input: 


Outputs: 




Discharge air 

tempering* 


ventilation* 


see: 


page 23 


on page 24 

Input: 




page 24 


on page 20 


Figure 14 on page 47 shows all required and optional components connected 

for heat pump applications. 

46 CNT-SVX12C-EN

24 Vac 

H 

N 

LonTalk 

In 

Out 

Figure 14. Wiring diagram for heat pump applications 


AC POWER 

AC OUT 








Common 

ECONOMIZER 


HVAC UNIT 


ANALOG INPUTS 

ZONE SENSOR 

SERVICE 


COMM5 

LED 

Occupancy 

or generic 

(optional) 

Tri-state 

modulating 

economizer 

(optional) 

Dry contacts 

only 

+ _ 

GND 



Power* 

Fan 

R G Y1 Y2 O W1 


sensor 

(optional) 

Fan status or 

generic 

(optional) 



Reversing valve 

5NC 

BINARY OUTPUT 

Discharge air 

temperature 

Outdoor air 

temperature 

(optional) 

Auxiliary heat 


STATUS 

LED 

LonTalk 

1 

2 

3 

4 

5 

On 

Cancel



Set the DIP switches on the circuit board for the heat pump configuration. 

The correct settings are shown in Figure 15. 

Figure 15. DIP switch settings for heat pump configuration 

ON DIP 

1 2 3 4 

ON DIP 

1 2 3 4 

ON DIP 

1 2 3 4 

Heat pump 

without economizer 

Heat pump with 

economizer 

48 CNT-SVX12C-EN

Binary outputs for heat pump applications 

Binary outputs for heat pump 


This configuration supports heat pump applications that have the following 

components: 



• One or two compressors 

• Reversing valve 

• Auxiliary heat 

• Exhaust fan 

The Tracer ZN517 controller has eight binary outputs. Each binary output 


each output for heat pump applications. 

Table 17. Binary outputs for 2-heat/2-cool applications 




G Supply fan 

1 (Y1) Compressor 1 

2 (Y2) Compressor 2 

3 (O) Reversing valve 

4 (W1) Auxiliary heat 

5NO/5COM/5NC (binary output 5) Exhaust fan/generic/occupancy 





• Not used. 




mode. 







CNT-SVX12C-EN 49


Binary inputs for heat pump 





4-cool applications. Each function is explained in the succeeding paragraphs. 

For an explanation of the diagnostics generated by each binary 

input, see “Table of diagnostics” on page 79. For more information about 

how the controller operates, see Chapter 8, “Sequence of operations for 

the heat pump configuration”.” 

Table 18. Binary inputs for heat pump applications 














page 56.) 





Function 






50 CNT-SVX12C-EN

Analog inputs for heat pump applications 

Analog inputs for heat pump 


The Tracer ZN517 controller has five analog inputs. Table 19 describes 

the function of each input for heat pump applications. Each function is 




Chapter 8, “Sequence of operations for the heat pump configuration”. 

Table 19. Analog inputs for heat pump applications 

Analog input 



Function 






Note: 




Table 20. 

Table 20. AI1 configuration options and associated measurement 

ranges 



(4 mA=0%; 20 mA=100%) 


(4 mA=0 ppm; 20 mA=2000 ppm) 


(4 mA=0% RH; 20 mA=100% RH) 



Note: 



to the AI1 terminal. (Wiring is dependent on the specific applica- 

CNT-SVX12C-EN 51


tion.) The sensor communicates a value of 0–100% to the BAS. This configuration 


For the CO2 measurement configuration, a 4–20 mA sensor must be hardwired 

to the AI1 terminal as shown in Figure 16. The sensor will transmit 

a 0–2000 ppm value to the BAS. This configuration has no direct effect on 

Tracer ZN517 operation. If a valid value is established and then is no 

longer present, the controller generates a CO2 Sensor Failure diagnostic. 


CO 2 sensor 


4190 4100 or 4190 4101) 

Tracer ZN517 

24 Vac 


humidity sensor (see Figure 17) must provide a value to the controller. If 

a valid hard-wired or communicated relative humidity value is established 

and then is no longer present, the controller generates a RH Sensor 

Failure diagnostic and disables the dehumidification function. The RH 

sensor is used only to provide a valid humidity reading to a BAS; it does 

not affect the operation of the Tracer ZN517. 



{{ 

24 Vac 

GND +20 AI1 

+ – 

GND +20 AI1 

GND Out 

Tracer ZN517 

RH sensor 

Figure Note: 


numbers 4190 1109, 4190 7011, 4190 7012, 4190 7014).

Analog inputs for heat pump applications 


The AI2 analog input can function as either: 









value. 








on page 60.) 








Note: 








area. 






on page 56). 

Note: 



CNT-SVX12C-EN 53




























54 CNT-SVX12C-EN

Chapter 8 

Sequence of operations for 

the heat pump configuration 

A Tracer ZN517 unitary controller configured to control a heat pump will 

operate to maintain the zone temperature setpoint. This chapter discusses 

many of the operational sequences used to accomplish this goal. 



























CNT-SVX12C-EN 55

Chapter 8 Sequence of operations for the heat pump configuration 










(0–100%). 


Active zone 

temperature 

setpoint 

Difference 

Measured 

zone 

temperature 





on page 60). 


Calculated 

discharge air 

temperature 

setpoint 









Difference 

Measured 

discharge air 

temperature 




capacity 





56 CNT-SVX12C-EN



on page 61) 







mode options: 

• Occupied 




Occupied mode 




present. The fan runs as configured (continuous or cycling with compressor 

operation). The outdoor air damper closes when the fan is off. The 

temperature setpoints can be local (hard-wired), communicated, or stored 

default values (configurable using the Rover service tool or a BAS). 


In unoccupied mode, the controller operates to maintain the zone temperature 


with compressor operation. The outdoor air damper remains closed. The 












The fan runs as configured (continuous or cycling with the compressor). 

CNT-SVX12C-EN 57









cycling with the compressor). The outdoor air damper closes when the fan 

is off. The controller will remain in occupied bypass mode until either the 

CANCEL button is pressed on the Trane zone sensor or the occupied 

bypass time (configurable using the Rover service tool or a BAS) expires. 

The temperature setpoints can be local (hard-wired), communicated, or 

stored default values (configurable using the Rover service tool or a BAS). 










Rover service tool or a BAS) from 0 to 240 minutes (default value is 120 

minutes). When the occupied bypass time expires, the unit changes from 

occupied bypass mode to unoccupied mode. Pushing the CANCEL button 

momentarily sends a fixed resistance of 1.5 kΩ to the ZN analog input of 

the controller, which is interpreted as a timed override cancel request. A 

timed override cancel request will end the timed override before the occupied 

bypass time has expired and will transition the unit from occupied 

bypass mode to unoccupied mode. 















58 CNT-SVX12C-EN

Heating or cooling mode 




The heating or cooling mode can be determined in one of two ways: 

• By a communicated signal from a BAS or a peer controller 

• Automatically, as determined by the controller 

A communicated heating signal permits the controller to heat only. A 

communicated cooling signal permits the controller to cool only. A communicated 

auto signal allows the controller to automatically change from 

heating to cooling and vice versa. 

In heating and cooling mode, the controller maintains the zone temperature 

based on the active heating setpoint and the active cooling setpoint, 

respectively. The active heating and cooling setpoints are determined by 

the occupancy mode of the controller. 

When no communicated signal is present (stand-alone operation) or the 

communicated signal is auto, the controller automatically determines the 

heating or cooling mode. 

Fan operation 








Compressor operation 

The Tracer ZN517 supports heat pump applications with one or two compressors. 

The compressor(s) will cycle to meet zone temperature requirements. 

Compressor operation will be overridden by a preset 3-minute 

minimum on/off time delay in order to maintain oil return when the unit 

is either initially energized, manually reset, switched between modes, or 

cycled within a single mode. 

Reversing valve operation 

The reversing valve is configurable to energize in either the cooling mode 

(typical of Trane units) or the heating mode. Be sure to configure the 

reversing valve operation based on the heat pump manufacturer’s design. 

An energized valve will remain energized until a mode change (either 

CNT-SVX12C-EN 59


from cooling to heating or vice versa) is initiated. The reversing-valve 

operation is delayed after compressor shutdown to reduce noise due to 

refrigerant migration. The reversing valve will de-energize when a power 

failure occurs, or when the controller is set to off either through a communicated 

off signal or when the fan switch is set to OFF. 

Economizing 













requirements. 


on page 48). 














Enabled. 



position in direct response to the CO 2 level, regulating the amount of outdoor 


ventilation. Demand control ventilation requires that the two triac (3- 

60 CNT-SVX12C-EN


wire floating point) outputs be used to control the damper actuator. The 


500 ppm. The function executes with a 3-minute loop frequency to allow 

time for the sensor to respond. 









100% open. 





• Setpoint 













• Filter-maintenance timer 









CNT-SVX12C-EN 61







Fan off delay 


service tool) to allow the residual cooling or heating energy to be circulated 

through the system. 

Fan status 




62 CNT-SVX12C-EN

Chapter 9 

PID control 

This chapter will help you set up, tune, and troubleshoot proportional, 

integral, derivative (PID) control loops used in the Tracer ZN517 unitary 

controller. For more information about PID loops, see BAS-APG002, PID 

Control in Tracer Multi-Purpose Controllers. 

PID control requires the use of a Rover service tool. All PID factory 

defaults can be restored by clicking the Use Defaults button. 

What PID loops do 

A PID loop automatically controls an output to maintain a measured 

value at its setpoint by monitoring the error (the difference between the 

measured value and the setpoint). The loop performs proportional, integral, 

and derivative calculations to determine how aggressively to change 

the output. 

The goal of PID control is to reach the setpoint as quickly as possible 

without overshooting the setpoint or destabilizing the system and to 

maintain the setpoint consistently over time. If the system is too aggressive, 

it will overshoot the setpoint as shown in Figure 19. If it is not 

aggressive enough, the time to reach the setpoint will be unacceptably 

slow. 

Figure 19. The effects of PID aggressiveness 

Measured value 

Too aggressive (overshoot) 

Setpoint 

Initial point 

Ideal response 

Too slow 


Time

Chapter 9 PID control 

PID calculations 

PID algorithms perform three calculations: the proportional calculation, 

the integral calculation, and the derivative calculation. These calculations 

are independent of each other but are combined to determine the 

response of the controller to the error. 

Proportional calculation 

The proportional calculation responds to how far the measured value is 

from the setpoint. The larger the error, the larger the output of the calculation. 

The proportional calculation has a much stronger effect on the 

result of the PID algorithm than either the integral or derivative calculations. 

It determines the responsiveness (or aggressiveness) of a control 

system. Though some systems use only proportional control, most Trane 

controllers use a combination of proportional and integral control. 

Proportional-only control loops require an error to produce an output. If 

the setpoint and the process variable are the same, the error is zero, so 

the system does not have an output. In an HVAC system, this can cause 

an actuator to open or close. The integral calculation solves this problem. 

The recommended range for the proportional calculation in the Tracer 

ZN517 is 4–16. Restore PID factory defaults by clicking the Use Defaults 

button. 

Integral calculation 

The integral calculation responds to the length of time the measured 

value is not at setpoint. The longer the measured value is not at setpoint, 

the larger the output of the calculation. 

The integral calculation uses the sum of past errors to maintain an output 

when the error is zero. Line 1 in Figure 20 on page 65 shows that with 

proportional-only control, when the error becomes zero, the PID output 

also goes to zero. Line 2 in Figure 20 shows the integral output added to 

the proportional output. Because the integral calculation is the sum of 

past errors, the output remains steady rather than dropping to zero when 

the error is zero. The benefit of this is that the integral calculation keeps 

the output at the appropriate level to maintain an error of zero. 

The value of the integral calculation can build up over time (because it is 

the sum of all past errors), and this built-up value must be overcome 

before the system can change direction. This prevents the system from 

over-reacting to minor changes, but can potentially slow the system down. 

The recommended range for the integral calculation in the Tracer ZN517 

is 1–10. Restore PID factory defaults by clicking the Use Defaults button. 

64 CNT-SVX12C-EN

Figure 20. Integral output added to proportional output 

Output 

Proportional + integral 

output 

Derivative calculation 

Sampling frequency 

The derivative calculation responds to the change in error. In other 

words, it responds to how quickly the measured value is approaching setpoint. 

The derivative calculation can be used to smooth an actuator 

motion or cause an actuator to react faster. 

However, derivative control has several disadvantages: 

• It can react to noise in the input signal. 

• Setting derivative control requires balancing between two extremes; 

too much derivative gain and the system becomes unstable, too little 

and the derivative gain has almost no effect. 

• The lag in derivative control makes tuning difficult. 

• Large error deadbands, common in HVAC applications, render derivative 

control ineffective. 

Because of these disadvantages, derivative control is rarely used in HVAC 

applications (with the exception of steam valve controllers, which use 

derivative control to force the steam valve to react faster to changes). 


Error ≠ 0 Error = 0 

The sampling frequency is the rate at which the input signal is sampled 

and PID calculations are performed. Using the right sampling frequency 

is vital to achieving a responsive and stable system. Problems can arise if 

the sampling frequency is too slow or too fast in comparison to time lags 

in the system. 

Sampling too slowly can cause an effect called aliasing in which not 

enough data is sampled to form an accurate picture of changes in the 


2 

1 

Proportional-only 

output 

Time 

Proportional + integral 

output if proportional 

output has gone to zero


Figure 21. Sampling too slowly 

Duct static pressure 

Figure 22. Sampling at the correct rate 

Duct static pressure 

Sampling points 

Sampling points 

measured value. The system may miss important information and reach 

setpoint slowly or not at all. 

Figure 21 and Figure 22 show how aliasing can affect system response. In 

Figure 21 the sampling frequency is too slow. Because of this, many of the 

actual changes in duct static pressure are missed. In Figure 22 the sampling 

frequency is fast enough that the changes in static pressure are 

tracked accurately. 

Changes missed 

by system 

Time 

Time 

Problems also arise from sampling too quickly. Some systems have naturally 

slow response times, such as when measuring room temperature. 

Slow response times can also be caused by equipment lags. Since PID 

loops respond to error and changes in error over time, if the process variable 

(measured value) changes slowly, then the error will remain constant 

for an extended period of time. If the process variable is sampled repeatedly 

during this time, the proportional output remains about the same, 

but the integral output becomes larger (because it is the sum of past 

errors). When the control system does respond, the response is out of proportion 

to the reality of the situation, which can destabilize the system. 

66 CNT-SVX12C-EN


The control system should always wait to process the result of a change 

before making another change. 

Figure 23 shows the process variable if sampling times are too fast, 

acceptable, and barely acceptable. If the sampling frequency is too fast (2 

seconds), the process variable begins to oscillate and finally destabilizes 

because the PID loop output drives the actuator to extremes. 

Figure 23. System stability with different sampling times 

Process variable 

Sampling freq. = 10 s Sampling freq. = 20 s 

Sampling freq. = 2 s 

(system destabilizes if 

sampling freq. is too fast) 


Time


PID loop action 

The action of a PID loop determines how it reacts to a change in the process 

variable (such as a room temperature). A controller using direct 

action increases the output when the process variable increases. A controller 

using reverse action decreases the output when the process variable 

increases. 

Direct action 

Figure 24 shows the temperature when a system is cooling a space. If the 

error is large and the PID output is at 100%, the actuator and valve combination 

are fully open. As the process variable (room temperature) 

decreases, the error becomes smaller, and the controller closes the valve 

to reduce or stop cooling. Since the PID output and process variable move 

in the same direction (both decreasing), the loop is direct acting. 

Figure 24. Cooling a space 

Temperature 

Reverse action 

Figure 25 shows the temperature when a system is heating a space. If the 

error is large and the PID output is at 100%, the actuator and valve combination 

are fully open. If the process variable (room temperature) 

increases, reducing the error, the controller closes the valve to reduce 

heating. Since the PID output and process variable move in opposite 

directions, the loop is reverse acting. 

Figure 25. Heating a space 

Temperature 

Setpoint 


(temperature) 

Setpoint 


Error 

Error 


(temperature) 

Time 

Time

Figure 26. Error deadband 

Error deadband 

Error 

Process 

variable 

Setpoint 



Error deadband is typically used to minimize actuator activity. It can also 

be used to allow for some “slop” in the system sensors and actuator 

mechanics. Error deadband prevents the PID output from changing if the 

absolute value of the error is less than the error deadband. For example, 

in Figure 26 the error deadband is set at 2.0°F (1.1°C). As long as the 

absolute value of the error is less than the 2.0°F (1.1°C), the PID output 

cannot change. If the absolute value of the error does exceed 2.0°F 

(1.1°C), the PID output can change. 

Control 

Control 

As can be seen from Figure 26, error deadband is a means of limiting how 

often an actuator is controlled. If a PID loop controls a chilled water 

valve, this is not so important. But if a PID loop controls how many stages 

of cooling are being used, it is important to limit equipment cycling. 

Adjusting error deadband for modulating outputs 

In most applications, start with an error deadband of five or ten times the 

sensor resolution. For example, thermistors have a resolution of approximately 

0.1°F (0.06°C), so a good error deadband is 0.5°F (0.3°C). This setting 

ensures that the sensor reading has changed an adequate amount 

before the controller responds. 

IMPORTANT 

The error deadband should not be smaller than the sensor resolution or 

the controller will react to noise. 

Adjusting error deadband for staged outputs 

This section shows how to adjust the error deadband for staging applications. 

Finding the best error deadband for staged output applications is more 

difficult than for modulating outputs. Instead of using a continuous actuator, 

such as a chilled water valve, staged systems use binary outputs to 

start and stop pieces of equipment, such as fans in a cooling tower. Each 

CNT-SVX12C-EN 69


piece of equipment contributes a set amount to the final output. When 

setting the error deadband for staged outputs, the main goal is to reduce 

equipment cycling. 

Follow these guidelines when adjusting the error deadband: 

• Ask how tight control should be. A smaller error deadband results in 

tighter control, but control should not be so tight that the stages cycle 

on and off too frequently. 

For example, for a VAV air-handler turning on cooling stages, control 

can be somewhat loose. The individual VAV boxes control their valve 

to the space depending on the supply air temperature. If the supply 

air temperature is relatively warm, the VAV box allows more air flow. 

If the supply air temperature is somewhat cool, the VAV box constricts 

the air flow. 

• The contribution of each stage can change depending on external circumstances, 

so make adjustments under worst case conditions. 

Adjust the error deadband for cooling tower fan stages on very warm 

days, and adjust the error deadband for boiler stages on very cold 

days. 

With the preceding guidelines in mind, use the following procedure to 

determine error deadband. 

To adjust the error deadband for staged outputs: 

1. Run the system manually. 

If possible, do so under worst-case conditions for the site. Although it 

is not always possible for a technician to do this, it is possible for a 

well-trained customer. 

2. Find the smallest change in temperature, ∆T, that the first stage can 

contribute (the quantity could also be building static pressure for fans 

or flow for pumps). 

Pay attention to possible changes in external circumstances, such as 

the amount of water flow. If the system uses a lead-lag approach to 

the equipment, it will be necessary to find the minimum ∆T for all 

stages. 

3. Multiply ∆T by 0.45 (the error deadband should be slightly less than 

half of ∆T). 

Keep in mind the resolution of the sensor. You may need to round the 

error deadband to a more reasonable value. 

4. Run the system with the new error deadband. 

Cycling should be reduced as much as possible. 

70 CNT-SVX12C-EN

Other PID settings 

You can also use these settings to manage PID loops: 

Other PID settings 

• Proportional bias, which takes the place of derivative gain in proportional-only 

control 

• Minimum and maximum output, which limit the range of output of 

the PID algorithm 

• Enabled and disabled modes, which enable the PID output or disable 

it to a default value 

• Fail-safe mode sets the PID output to a “safe” value if the hardware 

input that provides the process variable fails. 

For more information, see BAS-APG002, PID Control in Tracer Multi- 

Purpose Controllers. 

Troubleshooting procedure 

IMPORTANT 

Remember to change only one thing at a time. 

Follow these steps to troubleshoot a PID loop: 

1. Make sure that the system is not in override. 

2. Graph the process variable, setpoint, and valve position over time to 

determine how the system performs. 

Look at the big picture. Can the system do what’s expected of it? What 

is happening to the process variable? Is it oscillating or failing to 

reach setpoint? Is the output oscillating? 

3. Check for failure conditions that are always true. 

4. Check PID settings for: 

• Output minimum incorrectly set to 100% 

• Output maximum incorrectly set to 0% 

• Sampling time that is too fast or too slow 

5. Check the system for disturbances from: 

• Bad actuator linkages 

• Faulty sensors 

6. Change PID gains. 

• Reduce gains if experiencing system overshoot, output at minimum 

or maximum, or cycling of output around setpoint 

• Increase gains if experiencing system undershoot 

CNT-SVX12C-EN 71


Tips for specific problems 

Table 21 provides tips for troubleshooting specific problems. 

Table 21. Tips for specific problems 

Problem Tips 

Measured value is cycling 

around setpoint 

Changing the sampling frequency 

The major cause of actuator cycling is time lags in the system. If a 10% 

change in PID output requires two minutes to affect the process variable, 

it does no good to have the sampling frequency set to two seconds. The 

integral contribution will build up before any significant change in error 

can be measured. A sampling frequency of 30 to 60 seconds would work 

much better in this situation. In other words, to fix a cycling system, slow 

down the loop! See “Sampling frequency” on page 65 for more information. 

Changing the gains 

Slow the sampling frequency 

Decrease PID gains 

Overshooting setpoint Reduce gains 

Undershooting setpoint Increase gains 

Output at maximum Ensure that minimum output is not set to 100% 

Output at minimum Ensure that maximum output is not set to 0% 

Be careful when changing PID gains. Never change gains unless the 

effects can be measured. Use a doubling/halving technique when increasing 

or decreasing gains. If the PID gains are set to 4, 1, and 0 respectively, 

and you are going to reduce them, try 2, 0.5, and 0. If the system now 

undershoots, try gains of 3, 0.75, and 0 respectively. 

72 CNT-SVX12C-EN

J1 (location of 

jumper for Rc, Rh 

terminals) 

Test button 

Service Pin button 

Service LED (red) 

Chapter 10 

Status indicators for 

operation and 

communication 

This chapter describes the operation and communication status indicators 

on the Tracer ZN517 unitary controller, including: 

• A description of the location and function of the Test button and Service 

Pin button and the light-emitting diodes (LEDs) 

• A complete list of the diagnostics that can occur, their effect on controller 

outputs, and an explanation of how to clear diagnostics and 

restore the device to normal operation 

Test button 

Use the Test button to perform the manual output test (see “Manual output 

test” on page 74), which verifies that the controller is operating properly. 

Figure 27 shows its location. 

Figure 27. Tracer ZN517 unitary controller circuit board 

Status LED (green) 

DIP switches 

LonTalk LED (yellow) 

CNT-SVX12C-EN 73

Chapter 10 Status indicators for operation and communication 

Manual output test 

The manual output test sequentially turns off and on all binary outputs 

to verify their operation. The test overrides normal operation of the controller, 

which is suspended while the test is being performed. 

Use the manual output test to: 

• Verify output wiring and operation. 

• Force compressor operation so that a technician can use test equipment 

to verify unit operation. 

• Clear diagnostics and restore normal operation (although not a primary 

function of the manual output test). 

Perform the manual output test either by repeatedly pressing the Test 

button to proceed through the test sequence or by using the Rover service 

tool. Table 22 on page 75, Table 23 on page 75, and Table 24 on page 76 

list the outputs in the sequence in which they are verified for the 2-heat/ 

2-cool, 4-cool, and heat pump configurations, respectively. 

To perform a manual output test: 

1. Press and hold the Test button for 3 to 4 seconds, then release the 

button to start the test mode. The green LED light goes off when the 

Test button is pressed, and then it blinks (as described in Table 26 on 

page 77) when the button is released to indicate the controller is in 

manual test mode. 

2. Press the Test button (no more than once per second) to advance 

through the test sequence. Table 22 shows the resulting activities of 

the binary outputs. 

3. The controller exits the test mode after the final step or after 1 hour 

passes, whichever comes first. 

Note: 

The outputs are not subject to minimum on or off times during 

the test sequence. However, the test sequence permits only one 

step per second, which enforces a minimum output time. 


Use the Service Pin button to verify that the controller is communicating 

on the network communications link, and to add devices and identify 

existing devices on the network communications link. See Figure 27 on 

page 73 for the location of the Service Pin button. 

For more information about the function of the Service Pin button, see the 

Rover Operation and Programming guide (EMTX-SVX01B-EN) or the 

Tracker Building Automation System Hardware Installation guide 

(BMTK-SVN01A-EN). 

74 CNT-SVX12C-EN

Table 22. Manual output test sequence for 2-heat/2-cool configurations 

Step (number of times 

Test button is pressed 

in sequence) 

Result 

Fan (G) 


1 Begins test mode Off Off Off Off Off Off Off 

2 Fan on1 On Off Off Off Off Off Off 

3 Compressor 1 On Off On Off Off Off Off 

4 Compressor 2 On Off On On Off Off Off 

5 Heat 1 On Off Off Off On Off Off 

6 Heat 2 On Off Off Off On On Off 

7 Outdoor air damper On On Off Off Off Off Off 

8 Generic/exhaust fan/occupancy On Off Off Off Off Off On 

9 Exit2 Off Off Off Off Off Off Off 

1 At the beginning of Step 2, the controller attempts to clear all diagnostics. 

2 This step exits the manual output test and initiate a reset to restore the controller to normal operation. 

Table 23. Manual output test sequence for 4-cool configurations 



in sequence) 

Result 

Fan (G) 



3 Compressor 1 On Off On Off Off Off Off 

4 Compressor 2 On Off On On Off Off Off 

5 Compressor 3 On Off On On On Off Off 

6 Compressor 4 On Off On On On On Off 







Economizer (OPN) 


Cool stage 1 (1) 




Heat stage 1 (3) 




Exhaust fan/generic/ 

occupancy 

(5NO/5COM/5NC) 


occupancy 

(5NO/5COM/5NC)


Table 24. Manual output test sequence for heat pump configurations 



in sequence) 

Result 

Fan (G) 



3 Reversing valve on On Off Off Off On Off Off 

4 Compressor 1 On Off On Off On Off Off 

5 Compressor 2 On Off On On On Off Off 

6 Compressors off On Off Off Off Off Off Off 

7 Auxiliary heat On Off Off Off Off On Off 






Interpreting LEDs 

The red LED on the Tracer ZN517 unitary controller (see Figure 27 on 

page 73) indicates whether the controller is not working properly (see 

Table 25). 




Table 25. Red LED: Service indicator 



LED activity Explanation 

LED is off continuously when power 

is applied to the controller. 

LED is on continuously when power 

is applied to the controller. 



occupancy 

(5NO/5COM/5NC) 

The controller is operating normally. 

The controller is not working properly, 

or someone is pressing the Service 

button. 

LED flashes once every second. The controller is not executing the 

application software because the network 

connections and addressing 

have been removed. 1 

1 Restore the controller to normal operation using the Rover service tool. Refer to 

EMTX-SVX01B-EN for more information.

Interpreting LEDs 

The green LED on the Tracer ZN517 unitary controller (see Figure 27 on 

page 73) indicates whether the controller has power applied to it and if 

the controller is in manual test mode (see Table 26). 

Table 26. Green LED: Status indicator 


LED is on continuously. Power is on (normal operation). 

LED blinks (one recurring blink). Manual output test mode is being 

performed and no diagnostics are 

present. 

LED blinks (blinks twice as a recurring 

sequence). 

LED blinks (1/4 second on, 

1/4 second off for 10 seconds). 

Manual output test mode is being 

performed and one or more diagnostics 

are present. 

The Auto-wink option is activated, 

and the controller is communicating. 

1 

LED is off continuously. Either the power is off, 

the controller has malfunctioned, or 

the Test button is being pressed. 

1 By sending a request from the Rover service tool, you can request the controller’s 

green LED to blink (“wink”), a notification that the controller received the signal 

and is communicating. 

The yellow LEDs on the Tracer ZN517 unitary controller (see Figure 27 

on page 73) indicate the controller’s communications status (see 

Table 27). 

Table 27. Yellow LED: Communications indicator 


LED is off continuously The controller is not detecting any 

communication (normal for standalone 

applications). 

LED blinks. The controller detects communication 

(normal for communicating 

applications, including data sharing). 

LED is on continuously. Abnormal condition. 

CNT-SVX12C-EN 77


Diagnostics 

In response to a diagnostic, the controller attempts to protect the equipment 

it is controlling by disabling all the outputs. When the diagnostic 

clears, the controller resumes normal operation. 

Diagnostic types 

The Tracer ZN517 has two types of diagnostics: informational and automatic 

(also referred to as nonlatching). Informational diagnostics provide 

information about the status of the controller. They do not affect machine 

operation. They can be cleared from the controller in one of the following 

ways: 

• By using the Rover service tool (see “Resetting a diagnostic” in 

EMTX-SVX01B-EN, Rover Operation and Programming guide.) 

• Through a building automation system (see product literature) 

• By initiating a manual output test at the controller (see “Manual output 

test” on page 74) 

• By cycling power to the controller. When the 24 Vac power to the controller 

is cycled off and then on again, a power-up sequence occurs. 

Automatic (nonlatching) diagnostics clear automatically when the problem 

that generated the diagnostics is solved. 

78 CNT-SVX12C-EN

Table of diagnostics 

Table 28. Diagnostics for the ZN517 unitary controller 

Diagnostics 

Table 28 describes each diagnostic that can be generated by the Tracer 

ZN517. 

Diagnostic Probable cause Consequences 

P Normal Default value until power-up 

control wait expires 

Normal Default value after power-up 

control wait expires 

Local Space Setpoint Failure Invalid or missing value for 

space setpoint 

Maintenance Required The maintenance required 

timer has expired 

Local Fan Switch Failure BI2 has not seen a contact 

closure for 60 seconds, indicating 

fan proving 

CO 2 Sensor Failure CO 2 input is invalid or 

missing 

None N/A 

None N/A 

Diagnostic 

type 

The controller uses default values. Informational 

Informational warning only. Informational 

All binary outputs are disabled. Automatic 

Demand control ventilation is 

disabled. 

Automatic 

Discharge Air Temp Failure Discharge air temperature 

input is invalid or missing 


Invalid Unit Configuration Invalid DIP switch setting Controller will not operate. Automatic 

RH Sensor Failure Relative humidity input is 

invalid or missing 

Dehumidification is disabled. Automatic 

Space Temperature Failure Space temperature sensor 

is invalid or missing 


CNT-SVX12C-EN 79


80 CNT-SVX12C-EN

Chapter 11 

General wiring information 

This chapter provides specifications and general information about wiring 

the Tracer ZN517 unitary controller. The controller requires wiring 

for: 

• Input/output terminals 

• AC power to the controller 

• Communication-link wiring, if the controller is to communicate with a 

building automation system (BAS) 

Input/output terminal wiring 

All input/output terminal wiring for the Tracer ZN517 unitary controller 

is application specific and dependant on the configuration of the controller. 

For application-specific wiring information and diagrams, see Chapter 

3, “Applications for the 2-heat/2-cool configuration”,” Chapter 5, “Applications 

for the 4-cool configuration”,” and Chapter 7, “Applications for the 

heat pump configuration”.” 

Wiring specifications 

Input/output terminal wiring must meet the following requirements: 

• All wiring must comply with the National Electrical Code and local 

codes. 

• Use only 18 AWG twisted-pair wire with stranded, tinned-copper conductors. 

(Shielded wire is recommended.) 

• Binary input and output wiring must not exceed 1000 ft (300 m). 

• Analog input wiring must not exceed 300 ft (100 m). 

• Do not run input/output wires in the same wire bundle with any ac 

power wires. 

CNT-SVX12C-EN 81

Chapter 11 General wiring information 

HVAC unit electrical circuit wiring 

The terminals labeled Rc and Rh are provided as inputs for 24 Vac power 

from the transformer(s) of the HVAC system. 

Note: 

The Tracer ZN517 is shipped from the factory with terminals 

Rc and Rh coupled with the jumper at J1 on the controller circuit 

board. 

Packaged units 

If the HVAC unit combines heating and cooling (referred to as a “packaged” 

unit), it will typically have one “R” transformer. For 24 Vac wiring 

of packaged units, the Rc terminal must be wired as shown in this 

procedure: 

1. Locate the jumper at J1 on the controller circuit board (Figure 28 on 

page 83). Place the jumper on both pins at J1 on the circuit board 

(Figure 29 on page 83). 

2. Wire the Rc terminal to the transformer on the unit (Figure 30 on 

page 84). 

Split systems 

If the unit is a split system (a unit with physically separate heating and 

cooling sections), there is typically a separate transformer for each function. 

For 24 Vac wiring of split systems, the Rc and Rh terminals must be 

wired as show in this procedure: 

1. Locate the jumper at J1 on the controller circuit board (Figure 28 on 

page 83). Remove the jumper from the pins at J1 on the circuit board 


2. Replace the jumper on one of the pins at J1 for possible future use. 

3. Wire Rc to the transformer for the cooling section of the unit 


4. Wire Rh to the transformer for the heating section of the unit 


82 CNT-SVX12C-EN

Figure 28. Location of J1 on Tracer ZN517 circuit board 

J1 (location of 

jumper for Rc, 

Rh terminals) 

Input/output terminal wiring 

Figure 29. Coupling and uncoupling terminals Rc and Rh for 24 Vac 

wiring of the HVAC unit 

For packaged units J1 For split systems 

J1 

Place the jumper on 

both pins at J1. 

Remove the jumper from 

one of the pins at J1. 

(Leave it on one of the pins 

for possible future use.) 

CNT-SVX12C-EN 83


24 Vac 

24 Vac 

H 

N 

H 

N 

Figure 30. Wiring for packaged heating and cooling units 

Primary 

Secondary, 24 Vac 

Tri-state 

modulating 

economizer 

(optional) 


Heat stage 1 

Figure 31. Wiring for split system applications 

Primary 


Tri-state 

modulating 

economizer 

(optional) 

*Wire the fan (G) to the appropriate section of the split system. 


Fan 


R G Y1 Y2 W1 W2 

Fan* 

Heat stage 2 

Rc Rh G Y1 Y2 W1 W2 


Heat stage 1 

Generic binary output (dry contact) 


Heat stage 2 

Primary 


Generic binary output (dry contact)

AC power wiring 

CAUTION 

Equipment damage! 

AC power wiring 

Complete input/output wiring before applying power to the Tracer 

ZN517 unitary controller. Failure to do so may cause damage to the controller 

or power transformer due to inadvertent connections to power 

circuits. 

�CAUTION 

Hazardous voltage! 

Make sure that the 24 Vac transformer is properly grounded. Failure to 

do so may result in damage to equipment and/or minor or moderate 

injury. 

IMPORTANT 

Do not share 24 Vac between controllers. 

All wiring must comply with National Electrical Code and local codes. 

The ac power connections are in the top left corner of the Tracer ZN517 

unitary controller (see Figure 32). 

Figure 32. Connecting ac power wires to the controller 

24 Vac unit 

transformer 

If you are providing a new transformer for power, use a UL-listed Class 2 

power transformer supplying a nominal 24 Vac (19–30 Vac). The transformer 

must be sized to provide adequate power to the Tracer ZN517 unitary 

controller (9 VA) and output devices, including relays and valve 

actuators, to a maximum of 12 VA per output utilized. The Tracer ZN517 

may be powered by an existing transformer integral to the controlled heat 

pump, provided the transformer has adequate power available and adequate 

grounding is observed. 


H 

N


Communication-link wiring and 

addressing 

The Tracer ZN517 unitary controller communicates with a BAS and with 

other LonTalk controllers via a LonTalk communication link. For instructions 

on LonTalk communication wiring and addressing, follow the 

requirements given in the Tracer Summit Hardware and Software Installation 

guide (BMTX-SVN01A-EN) or the Tracker Building Automation 

System Hardware Installation guide (BMTK-SVN01D-EN) or another 

BAS installation manual. 

86 CNT-SVX12C-EN

Chapter 12 

Troubleshooting 

This chapter outlines some general troubleshooting steps that should be 

performed if there is a problem with the operation of the equipment controlled 

by the Tracer ZN517 unitary controller. This chapter describes 

some common problems; however, it cannot describe every possible 

problem. 

If you encounter operational problems with the Tracer ZN517, you must 

first perform initial troubleshooting steps; see “Initial troubleshooting” on 

page 88. After this procedure, consult the tables in “Diagnosing operational 

problems” on page 88 for further troubleshooting assistance. 

CNT-SVX12C-EN 87

Chapter 12 Troubleshooting 

Table 29. Initial troubleshooting steps 

Initial troubleshooting 

Always perform the initial troubleshooting steps listed in Table 29 before 

moving on to the specific area of trouble. Perform the steps in the order 

they are listed. 

Step number Action Probable cause 

Step 1 Look at the red Service LED. If it is flashing once per second, the controller is 

not executing the application software because the network connections and 

addressing have been removed. For a complete explanation of this LED’s 

behavior, see Table 25 on page 76. 

Use the Rover service tool or a BAS to restore normal operation. See EMTX- 

SVX01B-EN for more information. 

Step 2 Look at the green Status LED. It should be on continuously during normal 

operation. A blinking Status LED indicates the Tracer ZN517 is performing a 

manual output test. For a complete explanation of this LED’s behavior, see 

Table 26 on page 77. 

Step 3 Take your meter (set to measure ac voltage) and measure the voltage across 

the ac-power terminals on the Tracer ZN517 (with ac wires connected). See 

Figure 32 on page 85. 

If you see approximately 24 V (21–27 V) on those terminals, the board is 

receiving adequate input power and you likely have a Tracer ZN517 circuit 

board problem. 

Step 4 Disconnect the ac wires from the input power terminals. Take your meter (set 

to measure ac voltage) and measure the voltage across the ac wires. If you 

see approximately 0 V, the board is not receiving the power it needs to run. 

Step 5 Reconnect the ac wires to the input power terminals. Perform the manual 

output test, which is described in “Manual output test” on page 74. 

If the outputs on the controller do not behave as described in the manual 

output test (page 74), then you are likely to have a Tracer ZN517 circuit board 

problem. 

Diagnosing operational problems 

Tracer ZN517 is 

not configured 

Tracer ZN517 is in 

manual output test 

mode 

Tracer ZN517 circuit 

board problem 

Input power problem 

Tracer ZN517 circuit 

board problem 

After you have performed the initial troubleshooting steps, refer to the 

succeeding tables in this chapter to further diagnose the following operational 

problems: 

• Fan does not energize (Table 30 on page 89) 

• Heat does not energize (Table 31 on page 90) 

• An outdoor air damper stays closed (Table 32 on page 90) 

• An outdoor air damper stays open (Table 33 on page 91) 

88 CNT-SVX12C-EN

Table 30. Fan does not energize 

Probable cause Explanation 


Unit wiring The wiring between the controller outputs and the fan relays and contacts must be 

present and correct for normal fan operation. Refer to applicable wiring diagram. 

Failed end device The fan motor and relay must be checked to ensure proper operation 

Random start 

observed 

After power-up, the controller always observes a random start from 0 to 25 seconds. The 

controller remains off until the random start time expires. 

Power-up control-wait If power-up control-wait is enabled (non-zero time), the controller remains off until one of 

two conditions occurs: 

1) The controller exits power-up control-wait once it receives communicated information. 

2) The controller exits power-up control-wait once the power-up control-wait time expires. 

Cycling fan operation If configured to cycle with capacity, normally the fan cycles off with heating or cooling. 

The heating/cooling sources cycle on or off periodically with the fan to provide varying 

amounts of capacity to the zone. 

Unoccupied operation Even if the controller is configured for continuous fan operation, the fan normally cycles 

with capacity during unoccupied mode. While unoccupied, the fan cycles on or off with 

heating/cooling to provide varying amounts of heating or cooling to the space. 

Fan mode off If a local fan mode switch determines the fan operation, the off position controls the fan 

off. 

Requested mode off You can communicate a desired operating mode (such as off, heat, and cool) to the controller. 

If off is communicated to the controller, the unit controls the fan off. There is no 

heating or cooling. 

Diagnostic present For information about diagnostics, see Table 28 on page 79. 

No power to the controller 

If the controller does not have power, the unit fan does not operate. For the Tracer ZN517 

controller to operate normally, it must have an input voltage of 24 Vac. If the green LED is 

off continuously, the controller does not have sufficient power or has failed. 

Unit configuration The controller must be properly configured based on the actual installed end devices and 

application. If the unit configuration does not match the actual end device, the valves may 

not work correctly. 

Manual output test The controller includes a manual output test sequence you can use to verify output operation 

and associated output wiring. However, based on the current step in the test 

sequence, the unit fan may not be on. Refer to the “Manual output test” on page 74. 

CNT-SVX12C-EN 89


Table 31. Heat does not energize 


Unit wiring The wiring between the controller outputs and the electric heat contacts must be present 

and correct for normal electric heat operation. Refer to applicable wiring diagram. 

Failed end device Check electric heat element, including any auxiliary safety interlocks, to ensure proper 

operation. 

Normal operation The controller controls electric heat on and off to meet the unit capacity requirements. 

Requested mode off You can communicate a desired operating mode (such as off, heat, and cool) to the controller. 

If off is communicated to the controller, the unit shuts off all electric heat. 

Unit configuration Check to make sure unit is not in the 4-cool configuration. 

Communicated disable 

Numerous communicated requests may disable electric heat, including an auxiliary heat 

enable input and the heat/cool mode input. Depending on the state of the communicated 

request, the unit may disable electric heat. 



sequence, the electric heat may not be on. Refer to the “Manual output test” on page 74. 


No power to the controller 

Table 32. Outdoor air damper remains closed 

If the controller does not have power, electric heat does not operate. For the ZN517 controller 

to operate normally, you must apply an input voltage of 24 Vac. If the green LED is 

off continuously, the controller does not have sufficient power or has failed. 


Unit wiring The wiring between the controller outputs and the outdoor air damper must be present 

and correct for normal outdoor air damper operation. Refer to applicable wiring diagram. 

Failed end device Check damper actuator to ensure proper operation. 

Normal 

operation 

Warm up and cool 

down 

The controller opens and closes the outdoor air damper based on the controller’s occupancy 

mode and fan status. Normally, the outdoor air damper is open during occupied 

mode when the fan is running and closed during unoccupied mode. 

The controller includes both a morning warm up and cool down sequence to keep the 

outdoor air damper closed during the transition from unoccupied to occupied. This is an 

attempt to bring the space under control as quickly as possible. 

Requested mode off You can communicate a desired operating mode (such as off, heat, or cool) to the controller. 

If off is communicated to the controller, the unit closes the outdoor air damper. 



sequence, the outdoor air damper may not be open. Refer to the “Manual output test” on 

page 74. 


90 CNT-SVX12C-EN

Table 32. Outdoor air damper remains closed (Continued) 



Unit configuration The controller must be properly configured based on the actual installed end devices and 

application. If the unit configuration does not match the actual end device, the outdoor air 

damper may not work correctly. 

No power to the 

controller 

Table 33. Outdoor air damper remains open 

If the controller does not have power, the outdoor air damper does not operate. For the 

ZN517 controller to operate normally, you must apply an input voltage of 24 Vac. If the 

green LED is off continuously, the controller does not have sufficient power or has failed. 


Unit wiring The wiring between the controller outputs and the outdoor air damper must be present 

and correct for normal outdoor air damper operation. Refer to applicable wiring diagram. 

Failed end device Check damper actuator to ensure proper operation. 

Normal 

operation 

The controller opens and closes the outdoor air damper based on the controller’s occupancy 

mode and fan status. Normally, the outdoor air damper is open during occupied 

mode when the fan is running and closed during unoccupied mode. 



sequence, the outdoor air damper may be open. Refer to the “Manual output test” on 

page 74. 

Unit 

configuration 

The controller must be properly configured based on the actual installed end devices and 

application. If the unit configuration does not match the actual end device, the outdoor air 

damper may not work correctly. 

CNT-SVX12C-EN 91


92 CNT-SVX12C-EN

Index 

Numerics 

24 Vac wiring, 85 


Analog inputs, 15–18 

Binary inputs, 14 

Binary output 5 (5NO/5COM/5NC), 

13 

Binary outputs, 13–14 

Demand control ventilation, 24 

DIP switch settings, 12 

Discharge air temperature input, 17 

Discharge air tempering, 24 

Economizing, 17, 23 

Exhaust fan output, 13 

Fan off delay, 25 

Fan operation, 23 

Fan status, 25 

Fan status input, 14 

Filter-maintenance timer, 25 

Generic binary input, 14 

Generic binary output, 13 

Manual output test sequence, 75 

Occupancy modes, 20 

Occupancy or generic input, 14 

Occupancy output, 13 

Outdoor air damper operation, 22 

Peer-to-peer data sharing, 23 

Required and optional components, 

10 

Required and optional inputs and 

outputs, 10 

Sequence of operations, 19–25 

Temperature setpoint input, 18 

Timed override control, 22 

Unit protection strategies, 24 

Wiring diagram, 11 

Zone temperature input, 18 

4-cool configuration 



Binary output 5 (5NO/5COM/5NC), 

31 

Binary outputs, 31 



Discharge air temperature input, 35 











Manual output test sequence, 75 




Outdoor air damper operation, 40 


Required and optional components, 

28 

Required and optional inputs and 

outputs, 28 








A 

AC power wiring, 85 

Actuator 

Minimizing activity with error 

deadband, 69 

Actuators, damper, 6 

Additional application-dependent 

components, 6 

Agency listing/compliance, 4 

Analog inputs 

AI1 (Universal 4–20 mA), 15, 33, 51 

AI1 configuration options, 15, 33, 

51 

AI1 configured for CO2 

measurement, 16, 34, 52 

AI1 configured for RH 

measurement, 16, 34, 52 

AI1 generic configuration, 15, 33, 51 

AI2 (Outdoor air or generic 

temperature), 17, 35, 53 

AI2 configuration options, 17, 35, 53

Index 

AI2 generic temperature 

configuration, 17, 35, 53 

Generic temperature, 17, 35, 53 

Analog inputs, 2-heat/2-cool 

DAT (Discharge air 

temperature), 17 

SET (Temperature setpoint), 18 

Table, 15 

ZN (Zone temperature), 18 

Analog inputs, 4-cool 




Table, 33 


Analog inputs, heat pump 




Table, 51 


Applications 

Heat pump, 45 

Rooftop units, 9, 27, 31 

Split systems, 9 

Applications, 2-heat/2-cool, see 2heat/2-cool 

configuration 

Applications, 4-cool, see 4-cool 

configuration 

Applications, heat pump, see Heat 

pump configuration 

B 

BAS communication, 1, 86 

Binary inputs, 2-heat/2-cool 

BI1 (Occupancy or generic), 14 

BI2 (Fan status), 14 

Table, 14 

Binary inputs, 4-cool 



Table, 32 

Binary inputs, heat pump 



Table, 50 

Binary output 5 (5NO/5COM/5NC) 

2-heat/2-cool, 13 

4-cool, 31 

Heat pump, 49 

Binary outputs 

2-heat/2-cool, 13–14 


Configuration options for binary 

output 5 (5NO/5COM/5NC), 13, 

31, 49 

Heat pump, 49 

Binary outputs, 2-heat/2-cool 

Exhaust fan, 13 

Generic, 13 

Occupancy, 13 

Overriding, 14 

Table, 13 

Binary outputs, 4-cool 


Generic, 31 

Occupancy, 31 


Table, 31 

Binary outputs, heat pump 


Generic, 49 

Occupancy, 49 


Table, 46, 49 

Building automation system 

communication, 1, 86 

C 

Calculations 

In PID loops, 64–65 




Heat pump, 56 

CE, see Agency listing/compliance 

Circuit board 

Diagram, 73 

jumper (J1) location, 83 

CO2 measurement input, 16, 34, 52 

Compliance 

Compressor operation, 59 

Configuration options 

AI1 (Generic, CO2, or RH), 15, 

33, 51 

AI2 (Outdoor air or generic 

temperature), 17, 35, 53 

BI1 (Occupancy or generic), 14, 

32, 50 

Binary output 5 (exhaust fan, 

occupancy, or generic), 13, 31, 

49 

Configurations 

2-heat/2-cool, 9–25 

4-cool, 27–43 

Heat pump, 45–62 


D 

Damper actuators, 6 

Demand control ventilation, 24, 42, 

60 

Derivative calculation, PID loops, 65 

Derivative control, 65 

Diagnosing operational problems, 

87–91 

Diagnostics 

Automatic, 78 

CO2 Sensor Failure, 16, 34, 52, 

79 

Disable generation of, 15, 33, 51 

Discharge Air Temp Failure, 79 

General, 78 

Informational, 78 

Invalid Unit Configuration, 79 

Local Fan Switch Failure, 14, 32, 

50, 79 

Local Space Setpoint Failure, 18, 

36, 54, 79 

Maintenance Required, 25, 43, 

62, 79 

Nonlatching, 78 

Normal, 79 

P Normal, 79 

RH Sensor Failure, 16, 34, 52, 79 

Space Temperature Failure, 18, 

19, 36, 37, 54, 55, 79 

Table, 79 

Types, 78 

Dimensional diagram, 3 

Dimensions, 1 


2-heat/2-cool configuration, 12 

4-cool configuration, 30 

Economizing, 17, 35, 53 

Heat pump configuration, 48 

Direct action of PID loops, 68 

Discharge air temperature input 



Heat pump configuration, 53

Discharge air temperature 

sensors, 6 

Discharge air tempering, 24, 42, 60 

E 

Economizing, 17, 23, 35, 41, 53, 60 

Equipment 

Rooftop units, 13 

Split systems, 13 

Error deadband, 69–70 

Adjusting for modulating 

outputs, 69 

Adjusting for staged outputs, 

69–70 

F 

Fan off delay, 25, 43, 62 

Fan status, 25, 43, 62 

Fan status input 




Fans 

Operation, 23, 41, 59 

Troubleshooting, 89 

Filter-maintenance timer, 25, 43, 61 

Free cooling, see Economizing 

G 

Gains 

Changing, to troubleshoot 

specific problems, 72 

Generic 

Temperature input, 17, 35, 53 

Generic binary input 



Heat pump, 50 

Generic binary output 



Heat pump, 49 

GND terminal, analog inputs, 15, 

33, 51 

Grounding power transformers, 85 

H 

Heat failure, troubleshooting, 90 

Heat pump applications, 45 

Components, 49 

Heat pump configuration 



Binary output 5 (5NO/5COM/ 

5NC), 49 

Binary outputs, 49 




Discharge air temperature input, 

53 











Heating or cooling mode, 59 

Manual output test sequence, 

76 




Outdoor air damper operation, 

58 


Required and optional 

components, 46 

Required and optional inputs 

and outputs, 46 

Reversing valve operation, 59 









Humidity 

Measurement input, 16, 34, 52 

HVAC packaged units 

Wiring, 82 


Index 

HVAC split systems 

Wiring, 82 


HVAC unit electrical circuit wiring, 

82–84 


I 

Input/output terminal wiring, 81 

Integral calculation, PID loops, 64 

Integral control, 64 

J 

Jumper (J1) location, 83 

L 

LEDs 

General, 73 

Interpreting green (status), 77 

Interpreting red (service), 76 

Interpreting yellow 

(communications), 77 

Location, 73 

LonTalk communication, 86 

Description, 1 

LonTalk protocol, see LonTalk 

communication 

M 

Manual output test, 74–76 

Manual output test sequence 



Heat pump, 76 

Mounting 

Cover, 8 

Diagram, 8 

Location, 7 

Operating environment, 2 

Procedures, 8 

N 

National Electrical Code, 81, 85

Index 

O 

Occupancy modes, 2-heat/2-cool 

General, 20 

Occupied, 21 

Occupied bypass, 22 

Occupied standby, 21 

Unoccupied, 21 

Occupancy modes, 4-cool 

General, 38 

Occupied, 39 



Unoccupied, 39 

Occupancy modes, heat pump 

General, 56 

Occupied, 57 



Unoccupied mode, 57 

Occupancy or generic input 




Operating environment, 2 

Outdoor air damper 

Operation, 22, 40, 58 

Outdoor air damper remains closed 


Outdoor air damper remains open 


Outdoor air or generic temperature 

Input, 17, 35, 53 

Outdoor air temperature input, 17, 

35, 53 




General, 74 

Heat pump, 49 

Overshooting the setpoint, 63 

P 

Peer-to-peer data sharing, 23, 41, 61 

PID loops, 63–72 

Action, 68 

Calculations, 64–65 

Definition, 63 

Derivative calculation, 65 

Direct action, 68 

Effects of aggressiveness, 63 

Error deadband, 69–70 

Integral calculation, 64 

Managing with additional 

settings, 71 

Overview, 63 

Proportional calculation, 64 

Reverse action, 68 

Sampling frequency for 

calculations, 65–67 

Tips for specific problems, 72 

Troubleshooting, 71–72 

Power requirements, 2, 4 

Power transformers, 6 

Power wiring, 85 

Power-up sequence, 19, 37, 55 

Product description, 1 

Proportional calculation, PID loops, 

64 

Proportional, integral, derivative 

(PID) loops, see PID loops 

Protection strategies 



Heat pump, 61 

R 

Rc, Rh terminal wiring, 82–84 

Coupling and uncoupling with 

jumper, 83 

Reverse action of PID loops, 68 


Rooftop units, 9, 13, 27, 31 

Rover, 1 

Rover service tool, 1, 4, 13, 18, 20, 

21, 22, 23, 24, 25, 31, 36, 38, 39, 

40, 41, 42, 43, 49, 54, 56, 57, 58, 60, 

61, 62, 63, 74, 76, 77, 78, 88 

S 

Sampling frequency, 65–67 

Changing, to troubleshoot 

specific problems, 72 

see LonTalk communication, 86 

Sensors 

Application-specific, 15, 33, 51 

CO2, 16, 34, 52 

Discharge air temperature, 6, 20, 

38, 56 

Occupancy, 14, 32, 50 

Table of options, 6 

Zone humidity, 16, 34, 52 

Zone temperature, 6 

Sequence of operations, 2-heat/2cool 



Economizing, 23 







22 


Power-up sequence, 19 



Sequence of operations, 4-cool 










40 





Sequence of operations, heat pump 









Heating or cooling mode, 59 



58 






96 CNT-SVX12C-EN


Function, 74 

Location, 73 

Setpoint, controlling with PID loop, 

63 

Settings 

PID loops, 71 




Heat pump, 56 

Specifications 

Agency listing/compliance, 4 

Dimensional diagram, 3 

Dimensions, 1 

Input/output terminal wiring, 81 

Power requirements, 2, 4 

Storage environment, 4 

Transformers, 85 

Split systems, 9, 13 

Status indicators for operation and 

communication 

General, 73 

Green LEDs, 77 

Manual output test, 74 

Red LEDs, 76 

Service Pin button, 74 

Test button, 73, 74 

Yellow LEDs, 77 

Storage environment, 4 

T 

Temperature sensors 

Discharge air, 6 

Table of options, 6 

Zone, 6 

Temperature setpoint input 

2- heat/2-cool configuration, 18 



Test button 

Function, 73 

Location, 73 

Thermistor, 54 




Heat pump, 58 

Transformers, 6, 85 

Troubleshooting 

U 

Fans, 89 

Heat failure, 90 

Initial steps, 88 

Outdoor air damper remains 

closed, 90 

Outdoor air damper remains 

open, 91 

PID loops, general, 71–72 

PID loops, specific problems, 72 

UL, see Agency listing/compliance 





Universal 4–20 mA, 15, 33, 51 

W 

Wiring 

AC power, 85 

Compliance with National 

Electrical Code, 81, 85 

Connecting ac power, 85 

General, 81–86 

HVAC packaged units, 82 

HVAC packaged units, diagram, 

84 

HVAC split systems, 82 

HVAC split systems, diagram, 84 

HVAC unit electrical circuit, 

82–84 

Input/output terminals, 81 

LonTalk communication, 86 

Network communication, 86 

Requirements and options for 2heat/2-cool 

configuration, 10 

Requirements and options for 4cool 

configuration, 28 

Requirements and options for 

heat pump configuration, 46 

Wiring diagram 




Index 


Z 

Zone temperature input 




Zone temperature sensors, 6

Index 

98 CNT-SVX12C-EN

Trane 

A business of American Standard Companies 

www.trane.com 

For more information contact your local Trane 

office or e-mail us at comfort@trane.com 

Literature Order Number CNT-SVX12C-EN 

File Number SV-ES-BAS-CNT-SVX12C-EN 0405 

Supersedes CNT-SVX12B-EN April 2003 

Stocking Location Inland 

Trane has a policy of continuous product and product data improvement and reserves the right to 

change design and specifications without notice. Only qualified technicians should perform the installation 

and servicing of equipment referred to in this publication.

Binary inputs for 2-heat/2-cool applications - Trane

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Binary inputs for 2-heat/2-cool applications - Trane

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