The characteristics of capacitive pressure transmitters are:

1. High output signal: The circuit of the pressure transmitter can directly convert a small change in capacitance into a high output signal without signal amplification. 
2. Good long-term stability: Compared with other similar products, the pressure transmitter offers higher stability. Unlike metal strain sensors, capacitive pressure transmitters exhibit minimal creep, aging, and temperature effects. These adverse factors have less impact on the output stability, with zero point stability reaching 0.05%FS/5year.
3. Mechanical deformation: A small change in the distance between the capacitor plates can produce a measurable voltage signal. This minimal mechanical deformation reduces hysteresis and non-repeatability errors, and significantly improves sensor response speed.
4. Wide measurement range: The SMT3151 Capacitive-Absolute Pressure Transmitter can accurately measure pressures from 25 Pa to 70 MPa, with extremely high stability.
5. High performance: The capacitive materials used are chemically and physically stable, resulting in high performance. These sensors offer accuracy up to ±0.2%FS and stability better than ±0.05%FS — performance levels hard to achieve with other sensing principles.

Absolute Pressure Transmitter Working Principle

Pressure (gauge pressure) / absolute pressure transmitter measures pressure with atmospheric pressure or vacuum as the reference. Only one port is connected to the process pipeline.

The working principle of a metal capacitive pressure (gauge/absolute) transmitter is as follows: When pressure is applied to the surface of the metal measuring diaphragm (elastic element) through the isolation diaphragm and pressure guide medium, the diaphragm slightly deforms (maximum ~0.1 mm). A high-precision circuit converts this deformation into a voltage signal linear with differential pressure. After linearization and temperature compensation, a dedicated chip converts it into a standard 4–20 mA or 1–5 V signal.

The working principle of a capacitive pressure or capacitive absolute pressure transmitter is the same as that of a differential pressure transmitter, except that the low-pressure chamber is exposed to atmospheric pressure or vacuum.

SMT3151 Capacitive-Absolute Pressure Transmitters

Humlex is a manufacturer of Capacitive-Absolute Pressure Transmitters. SMT3151 Capacitive-Absolute Pressure Transmitters adopts high-performance pressure-sensing chips. With advanced circuit processing and temperature compensation technology, it converts pressure changes into linear current or voltage signals .

SMT3151 Capacitive-Absolute Pressure Transmitters have HART communication, communication and self-diagnosis functions. Users use handheld terminals or fieldbus systems to transmit, read, display and input all working information and additional information of transmitters from a long distance.

There are many types of pressure sensors, such as resistance strain gauge pressure sensors, semiconductor strain gauge pressure sensors, Silicon piezoresistive pressure sensors, inductive pressure sensors, capacitive pressure sensors, resonant pressure sensors and capacitive sensors.

A capacitive sensor is a device that converts the measured change into a change in capacitance, which itself is a variable capacitor. Because this sensor has the characteristics of simple structure, small size, good dynamic response, high sensitivity, high resolution, and non-contact measurement, it is widely used in displacement, acceleration, vibration, pressure, pressure difference, liquid level, etc. Sub-content and other detection fields.

If you need to purchase Capacitive-Absolute Pressure Transmitters, or have any technical questions about Absolute Pressure Transmitters, please feel free to contact our engineers.