Common fault handling methods of pressure sensor

1. Transmitter output ≥ 20mA

1）Whether the transmitter power supply is correct solution: if it is less than 12VDC, check whether there is a large load in the circuit, and the input impedance of the transmitter load shall meet RL ≤ (transmitter power supply voltage - 12V) / (0.02A)Ω.

2）Does the actual pressure exceed the selected range of the intelligent pressure transmitter

Solution: re select the intelligent pressure transmitter with appropriate range.Whether the pressure sensor is damaged. Severe overload may sometimes damage the isolation diaphragm.Solution: it needs to be sent back to the manufacturer for repair.Whether the wiring is loose;Solution: connect the wire and tighten it, and check whether the wiring of the power line is correct.Solution: the power cord should be connected to the corresponding terminal.

2. Transmitter output ≤ 4mA output ≤ 4mA

1) Whether the transmitter power supply is normal

Solution: if it is less than 12VDC, check whether there is a large load in the circuit, and the input impedance of the transmitter load shall meet RL ≤ (transmitter power supply voltage - 12V) / (0.02A) Ω.

2) Does the actual pressure exceed the selected range of theintelligent pressure transmitter

Solution: re select the intelligent pressure transmitter with appropriate range, and check whether the pressure sensor is damaged. Severe overload will sometimes damage the isolation diaphragm.

Solution: it needs to be sent back to the manufacturer for repair.

3 Transmitter no output

1) Check whether the transmitter power supply is connected reversely.

2) Measure whether the power supply of the transmitter has 24V DC voltage;If there is no power supply, check whether the circuit is disconnected and whether the detection instrument is selected incorrectly (the input impedance shall be ≤ 250 Ω),etc.

3) If it is with a meter, check whether the meter is damaged (the two wires of the meter can be short circuited first. If the short circuit is normal, the meter is damaged). If the meter is damaged, it needs to be replaced.

4) Connect the ammeter in series into the 24V power supply circuit and check whether the current is normal. If it is normal, it means that the transmitter is normal. At this time, check whether other instruments in the circuit are normal.

3. Incorrect pressure indication

1) Whether the power supply of the transmitter is normal. If it is less than 12VDC, check whether there is a large load in the circuit. The input impedance of the transmitter load shall meet RL ≤ (transmitter power supply voltage - 12V) / | (0.02A) Ω.

2) Whether the referenced pressure value must be correct. If the accuracy of the referenced pressure gauge is low, it is necessary to replace the pressure gauge with higher accuracy.

3) Whether the range of the pressure indicating instrument is consistent with that of the intelligent pressure transmitter. The range of the pressure indicating instrument must be consistent with that of the intelligent pressure transmitter.

4) Whether the input and corresponding wiring of the pressure indicating instrument are correct.If the input of the pressure indicating instrument is 4 ~ 20mA, the output signal of the transmitter can be directly connected;If the input of the pressure indicating instrument is 1 ~ 5V, a resistance with an accuracy of one thousandth or more and a resistance value of 250 Ω must be connected to the input end of the pressure indicating instrument, and then connected to the input of the transmitter.

5) The input impedance of the transmitter load shall comply with RL ≤ (transmitter supply voltage - 12V) / (0.02A) Ω.In case of non conformity, corresponding measures can be taken according to different conditions: such as increasing the power supply voltage (but it must be lower than 36VDC), reducing the load, etc.

6) Whether the input terminal is open when the multipoint paper recorder does not record.If there is an open circuit, ① no other load can be carried;② Use other recorders with input impedance ≤ 250 Ω when there is no record.

7) Whether the corresponding equipment shell is grounded.The equipment shell needs to be grounded.

8) Whether it is wired separately from AC power supply and other power supplies.It needs to be wired separately from AC power supply and other power supplies.

9) Whether the pressure sensor is damaged. Severe overload sometimes damages the isolation diaphragm. If it is damaged, it needs to be sent back to the manufacturer for repair.

10) Whether there are sand and impurities in the pipeline to block the pipeline. If there are impurities, the measurement accuracy will be affected.Clean up impurities and add a filter screen in front of the pressure interface.

11) Whether the temperature of the pipeline is too high. The service temperature of the pressure sensor is - 25 ~ 85 ℃, but it is better to be within - 20 ~ 70 ℃ in actual use.If the temperature is too high, add a buffer pipe to dissipate heat. Before use, it is best to add cold water in the buffer pipe to prevent overheated steam from directly impacting the sensor, thus damaging the sensor or reducing its service life.