STX Signal Transmitter Installation and Operation ... - Kistler-Morse

Chapter 2. Hardware Installation
Wiring System
This section describes how to wire the junction
box, power, and auxiliary equipment to the
STX. Refer to the specifications in Appendix A
and the drawings in Appendix H:
• Stand-Alone STX — TI-SP.STX-02
• STX in Standard 19” Rack — TI-SP.STX-03
• STX in MVS — TI-MVS.STX-01
WARNING
All wiring must comply with
government or local codes.
Wiring Junction Box to STX
CAUTION
Do not route junction box cables in the
same conduit with AC power cables.
Notes
1. Seal all conduit fittings against
water entry. Install conduit drains
at conduit’s lowest elevation(s) to
allow condensation to drain.
2. All wiring routed between junction
boxes and STX must be
continuous (no splices).
Refer to Appendix H. Instructions are provided
for half-bridge and full-bridge sensors. Refer
to the sensor manufacturer’s manual for
wire/cable specifications.
Note
Full-bridge sensors — If voltage
decreases as weight is added, switch
the +In1 and -In1 wires.
Wiring Power
WARNING
When connecting power to this unit:
• Power wiring must comply with
the national wiring requirements
for the country in which the
equipment is installed.
• The ground conductor must be
connected to the Protective Earth
(PE) terminal.
Note
The standard lead colors for AC power
in North America are:
• Ground = Green
• Hot = Black
• Neutral = White
Wiring Current Output
The fully isolated 0-20/4-20 Current Transmitter
is an optional PCB that is factory-soldered
to the STX PCB. Refer to Appendix H.
External Current Loop
Power Supply
The STX’s Current Transmitter Loop is
powered by the STX power supply. However,
an external power supply may be desired for
some applications. The maximum allowable
voltage from the external power supply is
50 Vdc. The minimum allowable voltage is
based on the loop resistance, allowing a
2 Volt overhead for the output’s current
sensing. For example:
1000 ohms x 0.020 amps = 20 Volts
Minimum voltage =
20 Volts + 2 Volts (overhead) = 22 Volts
Wire the current transmitter external power
supply as shown in Appendix H. Move the
JP11 jumper on the STX PCB to the Ext pins.
Wiring Serial Communications
Refer to Appendix H.
Sealing Openings in
Stand-Alone STX Enclosure
After conduit and cable installation is complete,
seal around the openings in the STX
enclosure to prevent moisture seepage.
CAUTION
Only use Sikaflex 1A polyurethane
sealant or Dow Corning RTV 739
or RTV 738. Other sealants may
contain acetic acid, which is harmful
to electronics.
Refer to the instructions below and Appendix H:
• DC (standard) — STX operates on nominal
15 to 24 Vdc (actual 14.4 to 30 Vdc) power.
• AC (option) — STX operates on 100, 120,
or 230 Vac factory-set power.
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