A differential pressure sensor (DPS) is a sensor used to measure the difference between two pressures, typically used to measure the pressure difference between the two ends of a device or component.
The sensor, through a certain design structure or according to regulations, converts the change in pressure before and after into a change in the pressure-sensitive element built into the sensor. The output is then processed and modulated by the weak signal generated by the deformation of the pressure-sensitive element, or further processed by analog-to-digital conversion and chip computing to output an analog or digital signal.
Example: Working principle of a capacitive differential pressure transmitter ( differential pressure sensor ): The two pressures of the measured medium are introduced into the high and low pressure chambers of the pressure transmitter, acting on the isolation diaphragms on both sides of the δ element (i.e., the sensitive element), and transmitted to both sides of the measuring diaphragm through the isolation plates and the filling fluid inside the element. The measuring diaphragm and the electrodes on the insulating plates on both sides each form a capacitor.
When the pressures on both sides are inconsistent, the measuring diaphragm shifts, and the amount of displacement is proportional to the pressure difference. Therefore, the capacitances on both sides are unequal. Through oscillation and demodulation, this is converted into a signal proportional to the pressure. The signal is then modulated to obtain a modulated current. An A/D converter converts the demodulator's current into a digital signal, the value of which is used by the microprocessor to determine the input pressure value. The microprocessor controls the transmitter's operation. Additionally, it performs sensor linearization, resets the measurement range, performs engineering unit conversions, damping, square root calculations, sensor fine-tuning, and other operations, as well as diagnostics and digital communication. This enables display and control functions.
I. Working principle of differential pressure sensor
The working principle of a differential pressure sensor is that the pressure being measured acts directly on the diaphragm of the sensor, causing the diaphragm to produce a micro-displacement proportional to the water pressure. This causes a change in the resistance value of the sensor, and electronic circuitry detects this change and converts it into a standard measurement signal corresponding to the pressure.
Features of differential pressure sensors
High performance-price ratio
All-stainless steel structure design, compact size, lightweight, and easy to install.
Stable and reliable performance
Differential pressure range: 0~10kPa...2MPa
Withstanding static pressure up to 20MPa
II. Differences between differential pressure sensors and pressure sensors
1. The parameters measured are different: Differential pressure sensors measure relative pressure, that is, the pressure difference between two locations. Pressure sensors measure absolute pressure.
2. Different interfaces: The differential pressure sensor has two input ports for connecting two measuring points respectively; the pressure sensor has only one connection port.
3. Different concepts: Both differential pressure sensors and pressure sensors refer to the magnitude of the output signal based on the pressure difference between the two ends of the measured object. Depending on the reference point used for measurement, they can be further divided into three types: gauge pressure, differential pressure, and absolute pressure.
