NORMAL OPERATION AND ALARMS
During normal operation each control module will display the current gas
concentration on the display. If the sensor reading is below alarm level
then all the alarm relays and the visual alarm LED indicators on the front
panel should be off.
Alarms
Each PT920 control module is equipped with four (4) alarm relays. The
relays are used to activate relays on the main connection board. The
control module activates the alarm relays when the sensor reading
exceeds the programmed alarm set point. Also LEDs on the front panel of
the control module will also light up for visual alarm indication.
Standard alarm set points are programmed at the factory before shipment.
The user must verify the alarm set points and make changes if desired.
Refer to section on Programming Alarm Set points.
Factory Alarm Settings are:
Alarm # Alarm Level Alarm Type
Low Alarm
10
Non-Latching
High Alarm
15
Non-Latching
High-High
20
Non-Latching
Alarm Reset
Once the gas concentration has dropped below the alarm level the relay
will reset itself. However, this is true only if the relay is configured as non-
latching (NL). If the relay is configured latching then it must be reset
manually. To reset the latching alarm press and hold the push button on
the front panel until relays and LED indicators turn off. A master alarm
reset switch on the control module rack assembly can also be used to reset
the alarms. This will reset alarms on all control modules.
Note: If the gas concentration continues to be higher than the programmed alarm
set point the alarm will be activated again.
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