How pressure transmitters work

How pressure transmitters work

Simply put, the pressure transmitter uses sensors, demodulators, current detectors, amplifiers, etc. to convert the pressure change signal into a standardized signal that the controller can read. The current signal of 4~20 mA DC is mainly used. There are also 1~5 VDC voltage signals or communication signals. The types of pressure transmitters can be simply divided into: (1) Piezoresistive transmitters, mainly due to the piezoresistive effect of the piezoresistor when the semiconductor piezoresistive material is under pressure, the resistivity changes, making the electrical The bridge generates a voltage signal proportional to pressure, from which changes in pressure can be measured. (2) Capacitive transmitters use the measuring diaphragm and the electrodes on the insulating sheets on both sides to form a capacitor. The two pressures of the measured medium pass through the high and low pressure chambers and act on the isolation diaphragm numbers on both sides of the sensitive element. (3) Inductive pressure transmitters are generally composed of pointer pressure gauges and electronic remote transmission components. When the pressure causes the spring tube of the pressure gauge to deform and displace, the inner iron core will also be displaced, and the inductance will change, and this change value will be converted into a DC current/voltage signal. (4) The strain-type pressure transmitter is also measured by converting pressure into resistance value. Two pieces of strain gauges are glued to the strain tube along the axial and radial directions with special glue, and the measurement is carried out when the strain tube is converted into resistance value due to the pressure. Two pieces of strain gauges are glued to the strain cylinder along the axial and radial directions with special adhesive, when the strain cylinder changes due to the shape of the material.