GasSens
Gas Detection System
Section 2 - A14 Receiver Module
O & M Manual
A14-RK, 8/06
2 - 8
OPERATION
Startup
Receiver front panels contain four LED bar indicators and a 4 digit LED display. The digital
display indicates gas concentration in either PPM, PPB, or percent. The green LED bar is marked
with the gas symbol and units of measurement (PPM, PPB, or %) specified on the customer
order. LED bars also indicate WARNING, ALARM, and TROUBLE conditions.
12 VDC power for the receiver is supplied from the power supply module. When power is first
applied, the LED display will turn on and will step through three information displays. The first
number displayed is the full scale range. A 0-10 PPM unit will be indicated by "10.0" on the
display. After 3 seconds, the display will indicate the warning setpoint, the concentration at which
the warning relay will activate, with the WARNING lamp illuminated. After 3 seconds, the display
will indicate the alarm setpoint, with the ALARM lamp illuminated. At the end of this sequence, the
display will begin to indicate gas concentration. However, all alarm functions will be inhibited for 5
minutes while the system is allowed to stabilize. This is indicated by WARNING and ALARM
lamps flashing in an alternating pattern. During this period, alarms will not function, but the
display will indicate the presence of any gas that might be in the area of the sensor. Normally, the
display will spike when power first comes on, and will slowly recover to zero over the 5 minute
period in which alarms are inhibited.
NOTE:
Sensors may require up to 12 hours to stabilize after power up.
Alarm Acknowledge and Reset
The front panel of the receiver contains one button, marked
A/R
, which is used for a number
of different functions. When the receiver is in normal operation, a gas leak that exceeds the
warning setpoint will cause the WARNING indicator to flash and the internal horn to sound
intermittently. If the alarm setpoint is exceeded, the ALARM indicator will flash and the horn will
sound steadily. Pressing the
A/R
button the first time will silence the audible horn, and will change
the WARNING and ALARM indicators from flash to steady on. The indicator lamps will remain lit
until the gas condition has cleared. The WARNING indicator will automatically shut off when gas
concentration falls below the setpoint, but the ALARM indicator will remain lit. Pressing the button
after the alarm condition has cleared will reset the ALARM indicator.
Operation of the individual relays depends on the configuration selected for each one. As
shipped from the factory, relay 1 will energize when the WARNING indicator lights and will
automatically reset when the gas condition clears and the WARNING indicator shuts off. Relays 2
and 3 are configured to energize and latch when the ALARM indicator lights. These relays will
reset when the
A/R
button is pressed to reset the ALARM indicator. Changes in the relay
configuration switches will alter this operational sequence.
