Sensor Voltages - GasTech GTA-4100R Operator's Manual

NOTE: The next section contains some configuration examples for common sensors that can be
connected to the GTA-4100R.
CAUTION: If you select the 1.4-14V adjustable option, see the next section for details on setting the
specific voltage to the sensor.
3.2.4

Sensor Voltages

Sensor head voltages for each channel are set by adjusting the "Head Volt" potentiometer. This is P5 for the
top channel and P6 for the bottom channel on each GTA-4100R module.
These potentiometers are set to 6V at the factory prior to delivery of the system but will need to be re-
adjusted to compensate for voltage drops in cable runs or different sensors. For this reason, sensor head
voltages should be checked as part of the commissioning process or when changing to a different sensor type.
The procedure is as follows:
1. Before making any adjustments, place the 4100R module into isolate mode.
2. Unplug the top and bottom channel sensor input cables from the back plane.
3. Ignore any Fault and Alarm indications and allow the system to stabilise before proceeding further.
4. To check the top channel sensor voltage, connect a digital voltmeter between TP9 (negative lead) and
TP7 (positive lead)
Page 18
1.4-14V adjustable from the card
Zero Volts from the card (externally powered)
Sensor head
voltage adjust
for top channel
© 2008 GasTech Australia Pty Ltd