2.4 WIRING TO ALARM STATION
(Typical for Toxic and Combustible)
Figure 4 shows a sample wiring diagram to connect PT2008 alarm relays to an Alarm
Station. The typical alarm station consists of 2 distinct color strobe light and a buzzer or
siren. The color of strobe light visually distinguishes between the low toxic and
combustible gas alarm. The buzzer or horn is for high alarm for both toxic and
combustible. On PT2008 connection board three relays are configured in order to have
distinct low alarm for toxic and LEL combustible and a common high alarm (siren) for
both toxic and combustible. Alarm relay 1 is wired for Low toxic gas alarm, alarm relay 2
for low combustible alarm and alarm relay 3 for common high alarm. Assume the toxic
and LEL alarm levels are as listed in table below
Sample alarm levels / set-points
Sensor
Type
Low Alarm High Alarm
Toxic (H2S)
10
15
LEL
20
40
To achieve this alarm relays on the gas monitor must be configured as follows.
Given above alarm level and relay configuration and wiring to alarm station as shown in
figure 5 the audio and visual alarm devices are activated as outlined in the table below.
H2S Alarms
Alarm
Level
Relay #
Low Alarm
10
1
High Alarm
15
3
LEL Alarms
Alarm
Level
Relay #
Low Alarm
20
2
High Alarm
40
3
Wireless Gas Detection
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