Model 8670 SUREFLOW Room Pressure Controller Manual - TSI

Chapter 8
Control Menu
The SUREFLOW may be set up to control room pressure at different sensitivities and
different speeds for maximum performance. This Chapter is a guide for setting up the
control parameters for the SUREFLOW.
The CONTROL menu is used to select the control SENSITIVITY and the control
SPEED. Data in the CONTROL menu is stored by pressing the SELECT key after a data
change has been made. The unit will respond that the data is saved by indicating
"Saving Data" on the display and sounding three beeps.
If you are unfamiliar with the keystroke procedure to program the controller, please
read Chapter 4, "Structure of Instrument," for a detailed explanation.
Access Code An access code is used to prohibit unauthorized access to the CONTROL menu. If you
attempt to enter the CONTROL menu when the access code is enabled, "Enter Code"
flashes on and off on the display. To enter the menu, enter the CONTROL menu access
code found in Appendix E.
General
Discussion
Description of
the CONTROL
Menu Items
If the access code is entered correctly, the CONTROL menu will be accessed.
The SUREFLOW uses both integral and PID control methods. Integral control is used to
maintain the operating setpoint with stability for natural system fluctuations such as
static pressure shifts. PID control is used to return to the operating setpoint with
optimal speed when responding to large disturbances. Once the SUREFLOW is in PID
control, it continues to control in this mode until the operating setpoint is met.
Item
SENSITIVITY
Description
The SENSITIVITY item is used to select the integral
deadband which determines where the controller uses
integral control only, and where the controller enters PID
control. When this item is selected, a bar graph will be
shown on the display. There are 10 possible bars that
represent ±10 ft/min each.
Starting from the right side (with + sign), 10 bars displayed
indicates no deadband and the controller will always use PID
control (see WARNING below). With 9 bars displayed, the
integral deadband is ±10 ft/min; with 8 bars, the deadband is
±20 ft/min; and so on to no bars displayed where the
deadband is ±100 ft/min.
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