Sierra Monitor Corporation 5000 PIN Function Wire Color, Combustible Gas Sensor Wiring Pin Out

SMC sierra monitor corporation Sentry Instruction Manual - Version 6

3.Using a Sierra Monitor Model 1200-26 Gas Calibrator with a Sierra Monitor Model 5358- 00 calibration adapter, or Model 5360 Gas Delivery Fitting. Apply the calibration gas at a flow rate of 100 cc/min. until the signal out voltage stops changing (approx. 2 minutes). Then adjust span adj. potentiometer to the calculated value.

4.Remove the calibration gas and wait for the voltage to drop. If the voltage is below 0.30 VDC the procedure is complete. If the voltage is above 0.30 VDC repeat the zero and span adjustments.

5.Calibrate the sensor using the instruction manual procedure.

•A LOW SENSITIVITY message during calibration indicates one of the two conditions for a combustible sensor:

•The zero gas voltage must be less than

.3 volts.

•The new span change (span voltage less zero voltage) must exceed 30% of the calculated span change.

For Example:

Zero gas voltage= .20 VDC Span voltage = .43 VDC

Span change is .43-.2 = .23 VDC

As the calculated span value (from step 5 above) is 1.03, the calculated span change is: 1.03-.2 = .87

By calculation: 30% of .87 = .26

The new span change (.23) is less than 30% of the calculated span change so a

LOW SENSITIVITY message will be

displayed.

The LOW SENSITIVITY calculation is made to insure that the calibration does not adjust the electronics so that the "gain" is large enough to cause false alarms due to minor drift or due to minimal electronic noise.

7.5.4 SENSOR REPLACEMENT

If any of the above adjustments cannot be completed successfully the sensor and/or electronics will require replacement. To check the sensor unplug it from the electronics and remove from the housing so that continuity and resistance tests can be made. Table 7-4 provides the pin out for the sensor assembly.

PIN	FUNCTION	WIRE COLOR
1	DETECTOR	WHITE
2	COMPENSATOR	BROWN
3	CALIB. SW.	RED
4	DETECTOR	BLACK
5	DRAIN	BARE
6	CALIB. SW.	GREEN

Table 7-5

Combustible Gas Sensor

Wiring Pin Out

1.Detector element resistance should be between 1.5 to 2 ohms.

2.Compensator element resistance should be between 1.5 to 2 ohms.

3.Calibration switch should be open in normal operation and should close when the calibration magnet is applied.

If the sensor fails any of these tests it should be replaced. If the sensor passes these tests the electronics are suspect and BOTH the sensor and electronics should be replaced. (The electronics and sensor which are removed should be returned to the factory for evaluation).

When a new sensor is installed the following actions must be taken:

•Make the bridge voltage adjustment immediately to avoid over-voltage damage to the sensor.

•Use diagnostic code 0020 to establish nominal value calibration.

•Allow 24 hours for full stabilization of the sensor, recheck the zero and span adjustments and calibrate the sensor module.

SERVICE Page: 70