Pressure Transmitter
A pressure transmitter measures the pressure of a gas or liquid and converts it into a standardised electrical signal, most commonly 4–20 mA, often with HART or a digital fieldbus. A sensing element such as a piezoresistive, capacitive or resonant sensor deflects under pressure, and the electronics linearise and temperature-compensate the signal. Types include gauge, absolute and differential pressure transmitters; differential units are also used for flow and level measurement. Applications include process control, pump and compressor protection, and filter monitoring. Selection parameters include measuring range and turndown, accuracy, process connection, wetted materials, diaphragm seals for corrosive or hot media, IP rating, and hazardous-area certification such as Ex d or Ex ia under the IEC 60079 series. Performance evaluation follows IEC 60770, and safety instrumented applications may require SIL capability to IEC 61508.
Examples
- Pump discharge pressure monitoring
- Differential pressure across a filter
- DP flow measurement with an orifice plate