Sensor types for pressure and differential pressure transmitters

Capacitive, diffused silicon, strain gauge, etc

A pressure transmitter, also known as a differential pressure transmitter, is primarily composed of a pressure-sensing element, module circuitry, a display gauge, a housing, and process connection fittings. It can convert pressure signals of gases, liquids, etc., received as input, into standard current and voltage signals for use by secondary instruments such as indicator alarms, recorders, and regulators for measurement, indication, and process control. The measurement principle of a pressure transmitter is as follows: The process pressure and the reference pressure act on opposite ends of an integrated silicon pressure-sensitive element; the differential pressure causes the silicon chip to deform (by a very small amount, only in the μm range), which enables the full-dynamic Wheatstone bridge fabricated on the silicon chip, using semiconductor technology, to generate a voltage signal in the mV range that is proportional to the pressure, driven by an external current source. Due to the excellent strength of silicon materials, both the linearity of the output signal and the distortion metrics are very high. During operation, the pressure transmitter converts the physical quantity being measured into a voltage signal in the mV range, which is then sent to a differential amplifier with a high gain that can offset temperature drifts. The amplified signal is converted into a corresponding current signal through voltage-to-current conversion, followed by nonlinear correction, to ultimately produce a standard current-voltage signal that has a linear relationship with the input pressure. Pressure transmitters can be divided into general pressure transmitters (0.001 MPa to 20 MPa) and micro-differential pressure transmitters (0 to 30 kPa), depending on their pressure measurement range.

Classified by detection principle: Capacitive transmitters: Measure pressure or differential pressure by detecting capacitance. Inductive transmitters: The measured value (pressure/differential pressure) changes the inductance of the coil; these can be further divided into magnetoresistive, differential, and eddy current types. Piezoresistive transmitters: Also known as solid-state or diffused silicon transmitters, they utilize the piezoresistive effect of solids. Piezoelectric transmitters: Based on the piezoelectric effect of piezoelectric materials. Potentiometric transmitters: Operate on the basis of the position of movable contacts on a resistor. Frequency-driven transmitters: Force is proportional to frequency (single-crystal silicon resonance type)

Sensor types for pressure and differential pressure transmitters? Please ask your friends to share their own usage experiences, as well as their feelings or insights. Thank you! ! ! My hope is that through discussion, everyone will consider the differences in the performance of transmitters for these various types of sensors, the amount of maintenance required, and the ability to replace components in case of failures. I just feel that it’s not easy for users to understand the actual performance of some products. Once we know the details, it might affect our purchasing decisions. I feel that my understanding of the performance of products from some major brands is insufficient and incomplete.

Capacitors or silicon resonant transmitters are used in critical locations, while diffused silicon transmitters are used in less important areas. Brands such as RS, Chuanyi, and E+H can be used