1: gas detector can not be calibrated.
The reasons may be: the sensor is broken; the circuit board is faulty; the calibration gas is incorrect; there is no electricity or poor contact. So, the way to deal with it is to replace the sensor, replace the circuit board, use the correct calibration gas, turn on the power or turn on the wire.
2.The 4-20mA signal is incorrect.
The reasons may be: there is a problem with the circuit board; there is a problem with the instrument; the wiring is loose or broken; the wiring is incorrect. Therefore, according to the reasons, we can make countermeasures: replace the circuit board, read the instrument manual, connect the wiring, correct the wiring;
3: No relay switch contact output.
The reasons may be: there is a problem with the circuit board; the relay is broken; the wiring is loose or broken; the wiring is incorrect. Therefore, we can also find countermeasures according to the reasons: replace the circuit board, replace the relay circuit board, connect the wiring, correct the wiring.