Thread Content
First, let’s understand the structure and function of a conventional pressure transmitter. A pressure transmitter is mainly composed of three parts: a pressure sensor, a measurement conversion circuit, and process connection components. Its function is to convert the physical pressure parameters of gases, liquids, etc., detected by the pressure sensor, into standard electrical signals for use in display alarms, DCS systems, recorders, PLC systems, etc., for purposes such as display, measurement, control, and regulation. In these tasks, many different problems may arise, and it is then necessary to pay attention to the maintenance and protection of the pressure transmitters during operation. Next, let’s examine the specific precautions to be taken when using pressure transmitters: 1. First, check whether there is any signal interference around the pressure transmitter; if so, try to eliminate it, or connect the sensor’s shielding wire to the metal casing to enhance its resistance to interference. 2. The mounting holes should be cleaned regularly to keep them clean, thereby preventing the transmitter from coming into contact with corrosive or overheated media ； 3. When making the connections, pass the cable through the waterproof connector (accessory) or flexible tube and tighten the sealing nut to prevent rainwater and other substances from seeping into the transmitter housing via the cable. 4. When measuring gas pressure, the pressure tapping should be located at the top of the process pipeline, and the transmitter should also be installed above the pipeline, so that accumulated liquid can easily flow into it. 5. When measuring liquid pressure, the pressure tap should be located on the side of the process pipeline to prevent the accumulation of sediment. 6. A voltage higher than 36V should not be applied to the pressure transmitter, as this can easily cause damage. 7. During freezing in winter, transmitters installed outdoors must be equipped with anti-freezing measures to prevent the liquid in the pressure tap from expanding due to freezing, which could cause damage to the sensor. 8. When measuring steam or other high-temperature media, a condenser such as a buffer tube (coil) must be used to prevent the operating temperature of the transmitter from exceeding its limits. Moreover, an appropriate amount of water needs to be injected into the buffer tube to prevent overheated steam from coming into contact with the transmitter. Moreover, the buffer heat dissipation tube must not leak air. Example of installing a pressure transmitter for steam pipelines 9. When measuring liquid pressure, the transmitter should be installed in a location where it is protected from the impact of the liquid (water hammer effect), to prevent the sensor from being damaged by excessive pressure. 10. The pressure guide tube should be installed in a location with minimal temperature fluctuations ； 11. Prevent residue from accumulating in the conduit ； 12. The medium measured by the pressure transmitter must not freeze; once it freezes, the diaphragm can be easily damaged, as diaphragms are generally very thin.