Differential Pressure Sensors

The differential pressure transducer measures the pressure difference between two points. The difference between differential pressure sensors and pressure sensors is that they have two pressure interfaces. Differential pressure sensors are generally divided into positive pressure end and negative pressure. In general, the pressure of the positive pressure end of the differential pressure sensor should be greater than the pressure of the negative pressure section to measure.

How Does Piezoresistive Differential Pressure Sensor Work?

The piezoresistive differential pressure sensor applies the two pressures to be measured to the diaphragm with piezoresistive elements on both sides. Upon sensing the pressure, the corresponding diaphragm deforms and causes a change in the resistance of the piezoresistive element. Differential pressure is measured using the change in resistance of a piezoresistive element across a curved diaphragm.

It is important to note that most differential pressure sensors are designed to measure lower differential pressures, not high differential pressures, that's why the range of differential pressure transmitters is 0~0.35 bar... 35 bar. High differential pressure measurements can be made using two independent pressure transducers and the difference is calculated. 

The differential pressure transducer or differential pressure transmitter are all differential pressure sensors. It is called differently while means the same in most situations depending on the countries and companies as differential pressure transducers are mostly used in the USA.  In Micro Sensor, we call the sensitive element a differential pressure sensor that usually outputs a millivolt signal. The differential transducers and differential pressure transmitters usually output digital signals like 4mA DC-20mA DC, Modbus, HART, etc.

Precautions for Differential Pressure Sensor Installation

• Ensure that the pressure on the high-pressure side of DP sensors is not less than the pressure on the low-pressure side.

• When installing and using the pressure-sensitive element, please keep it as horizontal as possible. This approach is to reduce the influence of installation inclination angle on the measurement accuracy of sensitive components.

• External resistors to compensate for temperature drift: It is recommended that the external resistors be connected as close as possible to the differential pressure-sensitive components.

The differential pressure transducers generally apply for differential pressure monitoring and control of water, oil, and gases. It also can measure the liquid height as a level sensor. Micro Sensor's differential pressure sensors and transmitters are suitable for differential pressure measurement of oil tanks, water tanks, and pipelines in industries like petroleum fields, chemical plants, etc.