RC Systems ST-72, Instruction Manual

Page: 65 / 142

ST-72 User's Manual
Document: UM-1007 Revision Level A
59
LEDs indicate board
configuration.
J3 & J4 are interchangeable I2C connectors
used to add other option PCB assemblies to
the controller.
JP5 allows "zoning" of adjacent channel
alarms. All zoning jumpers are placed
vertically. DWG. exhibits channels 1-4 and
channles 5-7 creating two zones. All relays
in a zone switch togeather. Unused jumpers
may be stored horizantally.
TB3 & TB4 24VDC
inputs are tied together
making daisy chaining
the options easier.
Figure 3-3
3.2.3 OPTIONAL *BRIDGE SENSOR INPUT BOARD #10-0347
An optional 16-channel, 12 bit Bridge Sensor Input board allows popular gas detectors to
be connected directly to the ST-72 without additional signal conditioning or
transmitters. Up to eight dual channel 10-0192 modules may be installed in each 16-
channel 10-0347. Each 10-0192 channel is equipped with a bridge amplifier and balance
potentiometer and an adjustable switching regulator for setting the correct sensor
excitation voltage. A three position coarse gain jumper allows setting the gain of the
bridge amplifier. Fault supervision circuitry forces the ST-72 into a FAULT condition
upon sensor failure or removal.
This option may also be configured to accept 4-20mA inputs for mixing bridge sensors
and current loops into the same board. Placing any channel’s 2 position Bridge/4-20mA
jumper into 4-20mA position and installing the associated precision 100 ohm socketed
resistor allows 4-20mA signals to be applied to its C & A terminals. The 10-0192 sensor
modules are not required for channels accepting 4-20mA.
Channels receiving input data from this board should have the Data From: menu set for
Analog Input, as described in section 2.4.4 . The board default activates Cal Mode
described in section 2.4.4.4 needed to zero and span sensor readings. After performing