How to choose a pressure sensor
1, the pressure transmitter to measure what kind of pressure
To determine the maximum value of the measured pressure in the system, it is generally necessary to select a transmitter with a pressure range of about 1.5 times greater than the maximum. This is mainly in many systems, especially in hydraulic pressure measurement and processing, with peak and continuous irregular fluctuations, this instantaneous peak can damage the pressure sensor. Continued high pressure values or slightly exceeding the maximum calibration of the transmitter will shorten the life of the sensor, which will also degrade the accuracy. So you can use a buffer to reduce the pressure burr, but this will reduce the response speed of the sensor. So in the choice of transmitter to fully consider the pressure range, accuracy and stability.
2, what kind of pressure medium
Viscous liquid, mud will plug the pressure interface, solvent or corrosive substances will not damage the transmitter with these media in direct contact with the material. These factors will determine whether to select a direct separation membrane and materials that are in direct contact with the media.
3, the pressure transmitter needs much precision
Determine the accuracy of the non-linear, hysteresis, non-repetitive, temperature, zero offset scale, temperature effects. But mainly by the non-linear, hysteresis, non-repeatability, the higher the accuracy, the higher the price.
4, the pressure transmitter temperature range
Usually a transmitter will calibrate two warm sections, one of which is the normal operating temperature, the other is the temperature compensation range, the normal operating temperature range is the transmitter in the working state is not destroyed when the temperature range , In the range beyond the temperature compensation may not reach its application performance indicators.
The temperature compensation range is a typical range that is smaller than the operating temperature range. Operating the transmitter within this range will certainly achieve its due performance. Temperature change from two aspects of its output, one zero drift, the second is the impact of full-scale output. Such as +/- X% of the full scale, +/- X% of the reading, + +/- of the full scale over the temperature range, +/- X% of the reading over the temperature compensation range, , Without these parameters, will lead to uncertainty in use. The change in the output of the transmitter is caused by a change in pressure or by a temperature change. The temperature effect is the most complex part of knowing how to use the transmitter.
5, need to get what kind of output signal
MV, V, mA and frequency output digital output, choose what kind of output depends on a variety of factors, including the transmitter and the system controller or monitor the distance between the existence of "noise" or other electronic interference signal, the need for amplifier, The position of the amplifier. The most cost-effective solution for the use of mA-output transmitters for OEM devices with short distances between many transmitters and controllers.
If you need to enlarge the output signal, it is best to use a transmitter with built-in amplification. For long-distance transmission or the existence of strong electronic interference signal is best to use mA level output or frequency output.
If the RFI or EMI indicators are high in addition to the need to pay attention to select the mA or frequency output but also take into account the special protection or filter.
6, choose what kind of excitation voltage
The type of output signal determines how the excitation voltage is selected. Many pressure transmitters have built-in voltage regulator, so the power supply voltage range is larger. Some transmitters are quantitatively configured and require a stable operating voltage. Therefore, the operating voltage determines whether or not a sensor with a regulator is used. When selecting the transmitter, consider the operating voltage and system cost.
7, whether the need for interchangeability of the transmitter
Determine whether the required transmitter is able to accommodate multiple use systems. Generally speaking, this is very important, especially for OEM products. Once the product is delivered to the customer, the cost of the customer's calibration is quite large. If the product has good interchangeability, then even if the use of the transmitter will not affect the effect of the entire system.
8, the pressure transmitter overtime work need to maintain stability
Most transmitters will "drift" after over-work, so it is necessary to understand the stability of the transmitter before purchasing, which can reduce the trouble of future use.