RKI Instruments GD-K77D - Manual (Page 34)

29 • Alarms Model GD-K77D Operator’s Manual
Alarms
Alarm Types
There are two types of alarms: gas alarms and trouble alarms.
Gas Alarm. When the target gas reaches or exceeds an alarm set point, the gas alarm is
activated. The gas alarms are self-resetting. They will automatically clear once the alarm
condition has passed.
NOTE: The alarm point is factory set to 1/3 (first alarm) and 2/3 (second alarm) of full scale. To prevent a
false alarm, a three-second alarm time delay is provided.
Trouble Alarm. A trouble alarm is activated when a fault is detected in the Model GD-
K77D. Except for system fault (E-00), a trouble alarm is self-resetting. When the Model
GD-K77D returns to normal after a trouble alarm has occurred, the unit starts its warm-up
cycle, which runs for 25 seconds before Detection Mode commences.
Gas Alarm
Performance
• Display
Gas Concentration Display. Shows the gas concentration in parts per million (ppm) of the target gas.
When the gas detection range is exceeded, the following displays on the LED display:
Power Light (Green). Remains on.
Alarm Lights (ALM1 -- Yellow; ALM2 -- Red). When the concentration of the target gas
reaches or exceeds the ALM1 set-point, the yellow ALM1 light turns on. When the
concentration reaches the ALM2set-point, the red ALM2 light turns on.
• Analog Output
4-20mA Output. The output is proportional to gas concentration. If the concentration rises above full
scale, the maximum output will be 22 mA.