Pressure transmitter selection precautions Among the various types of instruments, transmitters are the most widely used and most common. The transmitters are generally divided into pressure transmitters and differential pressure transmitters. Transmitters are commonly used to measure pressure, differential pressure, vacuum, liquid level, etc. The transmitter has two-wire system (current signal) and three-wire system (voltage signal). Two-wire (current signal) transmitters are especially available; there are intelligent and non-intelligent points, and smart transmitters are more and more; Pneumatic and electric, the majority of electric transmitters; In addition, according to the application of intrinsic safety and explosion-proof type; in the selection, according to their own needs to make the appropriate choice.
First, the measured media compatibility
In the selection of the medium to consider the pressure interface and sensitive components, must consider the pressure interface and the material of the sensitive components, otherwise the outer diaphragm will be corroded after a short time of use, causing equipment and personal accidents caused by corrosion, so Material selection is very important.
Second, the influence of medium temperature and ambient temperature on the product
In the selection, the temperature of the measured medium and the ambient temperature should be considered. If the temperature is higher than the temperature compensation of the product itself, it is easy to cause the measurement data of the product to drift. When selecting, the actual working environment of the transmitter must be considered to avoid temperature sensitivity. The core caused the measurement to be inaccurate.
Third, the selection of pressure range
When selecting the type, the working pressure level of the equipment should be considered. The pressure level of the transmitter must be consistent with the application.
Fourth, the selection of pressure interface
In the selection process, strictly implement the pressure interface size used by the user, select the appropriate correct thread connection form, and confirm the product outline drawing, or the manufacturer can provide samples;
Fifth, the selection of electrical interfaces
In the selection, the user signal acquisition mode and field wiring should be confirmed repeatedly. The sensor signal should be connected with the user acquisition interface; the correct electrical interface and signal mode should be selected.
Sixth, pressure type selection
The instrument that measures absolute pressure is called an absolute pressure gauge. For ordinary industrial pressure gauges, the gauge pressure value is measured, that is, the pressure difference between absolute pressure and atmospheric pressure. When the absolute pressure is greater than the atmospheric pressure value, the measured gauge pressure value is called positive gauge pressure; when the absolute pressure is less than the atmospheric pressure value, the measured gauge pressure value is negative value, which is called negative gauge pressure, that is, vacuum degree. The meter that measures the degree of vacuum is called a vacuum gauge.
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