Scott QuadScan II 7400, Руководство по эксплуатации и техническому обслуживанию, Страница: 68 / 121

63 of 116
System Maintenance
General
Due to the unique microprocessor circuitry design and proven reliability of the QuadScan II, a set
maintenance schedule is not required. However, a visual alarm and relay check can be performed at
customer selected intervals to verify proper system operation.
CAUTION: CORRECTIVE DEVICES CONNECTED TO THE ALARM RELAY
CONTACTS MUST BE DISABLED BEFOR PERFORMING THE FOLLOWING TESTS
UNLESS IT IS INTENDED TO ALSO VERIFY THE OPERATION OF THE REMOTE
ANNUCIATORS.
Alarm/Relay Check
1. Remove the cover plate located on the lower bottom section of the enclosure.
2. Identify the Channel 1 current loop input wires located on TB1 and disconnect. The fail LED
will illuminate and the fail common relay will activate (change state). The internal horn will not
activate.
3. Connect a current generator with a range of 0 to 20 mA, (observe correct polarity), to the (+) IN
and (–) IN terminals on TB1. The fail LED will extinguish and the fail relay will return to normal
if the output is set to 4ma or above.
For toxic or combustible monitoring channels, follow steps 4 through 8. For oxygen
deficiency monitoring channels, follow steps 9 through 13.
4. Set the current generator for 4 mA and input to the system. The LCD will
indicate 0.0.
5. Set the current generator for 20mA to simulate a high toxic or combustible gas condition and
input to the system. The LCD will indicate the programmed full scale for a specific gas. The
warn and alarm LEDs will be illuminated and flashing, warn and alarm common relays will
activate (change state). The internal horn will be activated and the common horn relay will
also be activated. The fail LED and relay will not be activated.
6.
Reset the current generator to 4mA and input. The LCD display will return to 0.0. If the LEDs
and relays are still activated press the reset button and the LEDs and relays will now de-
activate.
7. Set the current generator to the programmed fault level to simulate an fault condition. The
Status LED will illuminate and flash yellow, the LCD will indicate a negative value