Common faults and solutions for pressure transmitters

Pressure transmitter is an important part of the automatic control system. The pressure transmitter is mainly used for the measurement and control of pressure parameters in industrial processes. It is widely used in petroleum, chemical, electric power and other fields. There are many types of pressure transmitters, and there are different classification methods depending on the working principle and use. The pressure transmitter is mainly used for remote display and control of pressure. It often works in high temperature, low pressure, corrosion, vibration and other environments, and the probability of failure is large. Therefore, the factors affecting the pressure transmitter and common faults are studied. It is very meaningful.

Pressure transmitters inevitably have various faults during use, and there are many influencing factors, such as filling liquid leakage between the diaphragm and the sensing element in the pressure transmitter, zero point and span shift, and unstable output. Will cause the pressure transmitter to drop in accuracy or even damage; weather factors will also affect the transmitter, such as lightning damage will damage the circuit of the transmitter bellows, resulting in communication failure; wet environment will damage the line; transmitter Unreasonable range selection can cause irreversible deformation of the pressure sensitive component. Here are a few common types of failures:

1. Line failure. When a line fault occurs, the computer displays an abnormal value, and the transmitter junction box is opened to check whether the line has a virtual connection, short circuit or disconnection. The fault is detected by using the power supply, the shaking insulation, and the quantity resistance.

2. Frequency conversion interference. When wiring is performed, various signal lines interfere with each other, especially when the power line and the signal line are in the same pipeline, and the interference is more serious. In this case, the transmitter does not communicate or even causes an error. This type of erroneous operation can be avoided by increasing the distance between the instrument cable and the power cable tray.

3. The pressure tube is faulty. There are three types of failures of the impulse piping, such as the clogging of the pressure piping, the leakage of the pressure piping, and the effusion of the pressure piping. The pressure clogging is generally caused by untimely discharge or dirty or sticky medium; The transmitter is connected to the power, the shut-off valve and other accessories are more, and the leakage point is increased; the effluent of the impulse tube is usually caused by the unreasonable pressure of the gas or the installation of the pressure tube, and the pressure of the pressure tube will affect measurement accuracy.

4. Electrical signal transmission failure. If the pressure transmitter is improperly used or maintained, it may easily cause the transmission of electrical signals. For example, in order to save time and place the transmitter near the device under test, the signal transmission distance is too far, and the signal may be disturbed or attenuated. When necessary, increase the cross-sectional area of the cable.

Pressure transmitter troubleshooting

1. The output signal is zero

When the pressure transmitter has zero pressure, it can be processed from the following aspects: first check whether there is pressure in the pipeline, whether the meter is normally powered, and then check whether there is a reverse polarity of the power supply, *** After checking the electronic circuit board, the pressure sensitive film head, the transmitter power supply voltage, and so on.

2. Add pressure and no reaction

If the pressure is not reactive, check whether the valve of the pressure tube is normal, whether the jumper switch of the transmitter protection function is normal, whether the pressure tube is blocked, check the zero point and range of the white feeder, and replace the sensor head.

3. Pressure variable reading deviation

When the pressure transmitter appears to have a high or low pressure reading, first check the pressure piping for leaks. Then check the valve on the pressure tube to fine tune the sensor. If there is still a problem, replace it with a new one. Sensor head.

4. Pressure variable reading is unstable

This problem can be checked by isolating the external interference source, checking whether the pressure guiding tube leaks, whether there is any debris in the pipeline, clothing or deformation when inspecting the diaphragm, and checking the pressure sensitive membrane head.


At present, the use of pressure sensors is very extensive. Whether it is a domestic transmitter or an imported transmitter, various faults may occur due to the working environment, improper human operation or self-use during use. Therefore, we must not only follow the standard specifications of the manual. Operation, but also to master the correct fault diagnosis, maintenance and maintenance knowledge, in order to ensure the life of the pressure sensor and measurement accuracy.