Parameters to pay attention to when selecting pressure sensors

Pressure sensors are increasingly used. To quickly and efficiently select the right pressure sensor, you need to have a comprehensive understanding of your application. The following are some parameters that need to be considered when selecting a pressure sensor. The editor will specifically introduce the parameters that need to be paid attention to when selecting a pressure sensor.

1. Select the type of pressure measurement: There are several types of pressure measurement, absolute pressure measurement, gauge pressure measurement, true gauge pressure measurement, and differential pressure measurement. Absolute pressure measurement refers to absolute pressure measurement, that is, pressure measurement relative to vacuum. Gauge pressure measurement refers to measurement relative to atmospheric pressure, but the atmospheric pressure in the actual environment is changing, so some sensors will seal an atmospheric pressure as a reference.

This sealed reference pressure will not change with the change of external air pressure, so this sealed reference pressure sensor is usually called a true gauge pressure sensor. Differential pressure measurement refers to the measurement of the pressure difference between two different media. It requires two pressure interfaces to transmit different pressure media.

2. Select the appropriate pressure range and overload pressure range. The pressure range of the sensor refers to the pressure range measured by the sensor, and the overload pressure refers to the maximum pressure value that the pressure sensor can withstand to ensure normal operation. Generally, the overpressure capacity of the pressure sensor is more than 1.5 times the measurement range.

The pressure range of the pressure sensor needs to be higher than the maximum pressure range in the application, but it cannot be too high. If the selected sensor range is higher, the sensor output signal variation range will be smaller during measurement, and the measurement accuracy will deteriorate.

3. Select the appropriate pressure interface. The pressure interface is the path for transmitting the medium pressure to the sensor. The materials of the pressure interface are usually ceramic, plastic, stainless steel, alloy, etc. Different materials need to be selected according to whether the pressure medium is corrosive or not. At the same time, the pressure interface also has different shapes, including volumetric shape and flush membrane shape. If the pressure medium is relatively viscous, it is recommended to use a flush membrane interface, which is not easy to cause medium deposition.

4. Select the appropriate electrical interface. The electrical interface is the data communication channel between the sensor and the external circuit or system. It needs to consider the type and size of the sensor's power supply voltage, the output signal type and the connection method. If the sensor does not have a signal conditioning circuit, its output has different output signals according to different principles of sensors, such as mV voltage signals, or capacitance change signals. At this time, customers need to choose to design signal processing circuits to convert signals into useful and recognizable signals.

Some sensors have signal conditioning circuits added after the sensor unit, and output analog signals such as 0-5V, 4-20mA, etc., while some also have digital conversion signals, such as output RS232, RS485 or PWM (pulse width modulation signals).

5. Choose the appropriate measurement accuracy. Different applications have different requirements for measurement errors, but the higher the measurement accuracy, the higher the cost of the sensor. Therefore, do not pursue high accuracy unilaterally in the application.

6. Choose the temperature range of the sensor. The sensor usually drifts with the change of temperature. In order to achieve high-precision measurement, the sensor usually has a temperature compensation function. Within the temperature compensation range, the sensor has the best measurement accuracy. In some high-temperature application environments, since most electronic components can only work within 85 degrees, you can choose a high-temperature sensor without an amplifier circuit to lead the measurement signal from the high-temperature area to the low-temperature area for signal processing.

In practical applications, sometimes it is also necessary to consider the resolution of the sensor. The resolution refers to the minimum pressure range that the pressure sensor can recognize. With the development of sensor technology, the pressure value that the sensor can recognize is getting smaller and smaller. In applications that require high resolution, customers can consider using sensors without amplifiers, choose high-performance amplifiers, and process the signals to achieve recognition of the minimum signal.