Faults code on Gas Detector SC111/112 General Monitors

During work in field sometime we find some problem with the gas detectors, so we have to know that faults code.

• F1= Fail to zero

This fault may occur during calibration for either of the following reason:
- faulty sensor : the sensor will need replacement
- Gas present : If the magnet was applied with a high level of gas present, the SC111 will not be able to obtain 'Zero' it indicates this by displaying 'F1', so ensure sensor is in clean air.

• F2 = Fail to calibrate

Latches until magnet is placed over the general monitors logo, this fault will occur if the unit is put into calibration mode or calibration check mode, but no gas has been detected within 3-6 minutes.

• F3 = Fail to Span

Latches until magnet is placed over the general monitors logo, this fault may occur during calibration:
Low gas : If the gas concentration applied to the unit does not give sufficient response for a valid 'SPAN' <use the correct gas concentration>
High gas : If the gas tester applied to the unit would give a perceived overflow condition. <use correct gas concentration>
Bad sensor : If the sensor response has gone bellow an acceptable level <replace sensor>

• F4 = Sensor Passive bead open circuit

Latches until power down, this fault occurs when: the sensor passive bead becomes open circuit or the sensor black and red leads become disconnected < check black and red wires or replace sensor as appropriate.

• F5 = Sensor active bead open circuit

latches until power down, this fault because the sensor active bead or white lead goes open circuit. < check white lead or replace sensor as appropriate.

• F6 = Power Low

This fault because the supply voltage between the brown and blue leads drops below 15Vdc approximately < ensure that supply is at least 20 V dc> note: maximum resistance per lead is 10 ohms for a 24 Vdc or 5 ohms for a 20 Vdc.

• F7 = EEPROM fails to verify

This fault occur during calibration when an attempt to verify the calibration parameters just written to non-volatile memory fails.<place the magnet over the General Monitors logo and the unit will attempt another EEPROM write and verify>

• F8 = Negative Sensor Drift

If negative sensor drift is greater than 5% but less than 10% FSD, then 'F8' is displayed and the analogue output goes to 3 mA, however if negative sensor drift is greater than 10% FSD then the analogue output goes to 0 mA and display continues to read 'F8'. This fault condition has a timeout of approximately one minute before the display and analogue output exhibit any change in status, and this condition does not latch