Analysis of Common Problems and Solutions for PDS Differential Pressure Transmitters

　　

（1） Line issues

　　

When the computer displays abnormal values, the first step is to open the junction box of the differential pressure transmitter and check whether the circuit is virtual, short circuited, or disconnected. This can be done by measuring the power supply, measuring resistance, shaking insulation, and other methods to determine and handle the problem.

　　

（2） Collection module or differential pressure sensor issues

　　

When troubleshooting the wiring issue, it is important to check if it is a problem with the acquisition module or differential pressure sensor. Use a multimeter to check whether the working power supply of the differential pressure transmitter is normal, and measure whether the output current value of the differential pressure transmitter is within the range of 4mA to 20mA (if it is the output voltage value, measure whether it is within the range of 0-5V), and confirm whether the output value is normal. If there is no output value, the differential pressure transmitter is damaged and needs to be replaced. If the on-site measurement value conversion matches the actual experience value, then there is no problem with the on-site instruments and measuring points, and the module is damaged and needs to be replaced. When the on-site measurement value is converted to match the computer display value, it indicates that there is a problem with the impulse pipe or differential pressure transmitter.

　　

（3） Pressure pipe issue

　　

(1) Blockage of the pressure pipe

　　

In actual production, use, and maintenance, due to delayed emissions or dirty, sticky, or particle like media, some may solidify over time, causing blockages in the pressure tube and hindering normal measurement. Therefore, in order to ensure the normal operation of the transmitter, it is necessary to regularly try to clear the pressure pipe.

　　

(2) Leakage of pressure pipe

　　

Due to the large number of accessories such as differential pressure transmitter contacts and globe valves, there are more leakage points and increased maintenance workload. Therefore, it is necessary to properly prevent corrosion of the pressure pipe and reduce the occurrence of sand holes in the pressure pipe; The screws at the interface of the pressure pipe should be tightened to prevent loosening.

　　

(3) Fluid accumulation in the pressure tube

　　

Due to incorrect gas flow pressure measurement methods or inadequate installation of pressure pipes, liquid accumulation inside the pressure pipes is often caused. The occurrence of this phenomenon often leads to inaccurate measurements, and if the transmitter range is very small, it may even cause some fluctuations in the transmitter output. Some literature suggests that the correct installation of the pressure pipe should be a continuous descent with a slope of not less than 1:12 from the horizontal, and there should be a height difference between the measuring point and the installation point. The pressure measuring point should be perpendicular to the wall of the tested equipment. In order to make the measurement more accurate, several pressure measuring heads can be set up, all of which are connected together to form a pressure equalization tube, and then led out through a pressure guiding tube. A drain valve is installed at the lowest point of the pressure equalization tube.

　　

These problems in use may seem simple, but they are easy to overlook. Therefore, users must pay attention to the above issues when using PDS differential pressure transmitters to avoid damaging the machine due to improper operation or installation, which may affect the quality of work.