How to deal with pressure transmitter output current greater than 20ma?

What to do if the output current of the pressure transmitter is greater than 20mA

As an important measuring instrument in industrial production, the stable and reliable operation of the pressure transmitter is crucial to ensuring production safety and improving product quality. However, in practical applications, we will inevitably encounter various problems, such as abnormal output current. Among them, pressure transmitter output current greater than 20mA is a relatively common fault phenomenon. If not handled in time, it may lead to system misjudgment and even cause safety accidents. This article will focus on this problem, analyze its common causes in simple terms and provide corresponding solutions.

Common reasons why the output current of the pressure transmitter is greater than 20mA

The output current of the pressure transmitter is greater than 20mA, indicating that the actual measured value exceeds the upper limit of the instrument, resulting in distortion of the output signal. There are many reasons for this situation, which can be roughly summarized into the following aspects:

1. Excessive pressure

This is the direct reason. When the measured pressure exceeds the upper limit of the measuring range of the transmitter, the output current will exceed the upper limit of 20mA. This situation usually occurs when the system pressure fluctuates greatly or there is a pressure shock.

2. Transmitter failure

Faults in the pressure transmitter itself may also cause abnormal output current. Common faults include:

The sensor diaphragm is damaged or aged, resulting in a decrease in measurement accuracy or signal distortion. The circuit board components are damaged, such as the amplifier circuit, A/D converter, etc., resulting in abnormal output signals. Loose wiring or poor contact may cause signal transmission problems.

3. Improper installation

Improper installation of the pressure transmitter has a great impact on the measurement accuracy and instrument life. Improper installation may also cause abnormal output current. Common installation problems include:

Improper installation location, such as installation in an environment with excessive vibration or high temperature. Wrong installation orientation, such as installing a flange transmitter on a vertical pipe. Excessive stress on the pipeline may cause deformation or damage to the transmitter.

4. Electrical interference

In the industrial site environment, various sources of electromagnetic interference are ubiquitous. If the pressure transmitter does not take anti-interference measures, it will be susceptible to interference and cause abnormal output signals. Common sources of electrical interference include:

Electromagnetic pulses generated by starting and stopping high-power motors. Electromagnetic radiation produced by high-voltage power lines. Radio signal interference.

How to deal with the problem that the output current of the pressure transmitter is greater than 20mA

For the above reasons, we can take corresponding measures to solve the problem of the output current of the pressure transmitter being greater than 20mA:

1. Check the pressure

First, confirm whether the system pressure exceeds the measurement range of the transmitter. If the pressure is too high, measures need to be taken to reduce the pressure, such as installing a pressure reducing valve or replacing a transmitter with a larger range.

2. Check the transmitter

The following methods can be used to check whether the transmitter is normal:

Disconnect the transmitter from the control system, and use a multimeter to measure the output current to see if it is within the normal range. Use a standard pressure source to calibrate the transmitter and observe whether the output current matches the actual pressure. Check the appearance of the transmitter to see if there is any obvious damage or abnormality.

If the transmitter is found to be faulty, it needs to be repaired or replaced in time.

3. Check the installation

Check the installation of the transmitter according to the installation specifications to ensure that the installation position, direction and connection method are correct. If problems are found, they need to be reinstalled or adjusted.

4. Strengthen anti-interference measures

The following measures can be taken to enhance the anti-interference ability of the transmitter:

Use shielded cables and make the shielding layer reliable Ground. Install a signal isolator between the transmitter and the control system. Choose a transmitter product with strong anti-interference ability.

Summary

The output current of the pressure transmitter is greater than 20mA, which is a difficult fault phenomenon and needs to be analyzed and dealt with based on the specific situation. In actual operation, it is recommended to first check whether the pressure is too high, then check the transmitter and installation conditions, and consider the impact of electrical interference. If the problem cannot be solved, it is recommended to contact technical personnel to deal with it to avoid causing greater losses.