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7-2. Operation - Gas Alarm
If the gas concentration exceeds the gas alarm set value, the alarm contacts will activate after the
alarm delay time, the red ALARM LED will start flashing, and ALARM1 or ALARM1 ALARM2 will
be shown on the LCD.
Note: During the alarm delay time, ALARM1 or ALARM1 ALARM2 flash, the alarm contact does
not activate, and the red ALARM LED does not flash.
Self-resetting: When the gas concentration falls below the gas alarm set value, the ALARM LED,
ALARM1 ALARM2 and relevant gas alarm contacts will automatically return to their normal
positions/status.
The table below lists the operation of each mode in the event of a gas alarm.
1
st
stage gas alarm
2
nd
stage gas alarm
Normal
operation(gas
monitoring)
Trouble alarm
(internal failure)
1
st
stage
gas alarm
2
nd
stage
gas alarm
LED
Green lit
Amber flash
Red flash
Red flash
LCD
Gas alarm
contact (ZA1)
OFF
(open position)
OFF
(open position)
ON
(closed position)
ON
(closed position)
Gas alarm
contact (ZA2)
OFF
(open position)
OFF
(open position)
OFF
(open position)
ON
(closed position)
Trouble alarm
open collector
(TA)
ON
(closed position)
OFF
(open position)
ON
(closed position)
ON
(closed position)
Red ALARM LED flashing
FLOW
SENS.
CONV.
ALARM1
ALARM1
ALARM2