First, the material of liquid connection.
We should consider the medium measured by pressure transmitter
. The contact medium of pressure transmitter is made of 316 stainless steel. If your medium is not corrosive to 316 stainless steel, then basically all pressure transmitters are suitable for your measurement of medium pressure.
If your medium is corrosive to 316 stainless steel, then we should use chemical seal, which not only can measure the pressure of the medium, but also can effectively prevent the contact between the medium and the liquid receiving part of the pressure transmitter, thus protecting the pressure transmitter and prolonging the life of the pressure transmitter.
Second, the accuracy level of pressure transmitter.
Each kind of electronic measuring meter will have precision error, but because the accuracy level of each country is different, for example, the accuracy of national standards such as China and the United States is the best part of the linearity of the sensor, that is, the accuracy between 10% and 90% of the measurement range we usually call, while the accuracy of European standards is the worst part of the linearity, that is, what we usually call the linearity. If the precision of the European standard is 1%, the precision of the Chinese standard is 0.5%. The precision of the pressure transmitter developed by Shanghai Jingta Instrument and Instrument Co., Ltd. is 0.2. Pressure transmitter. Please choose refined tower products.
Third, the range.
Generally, the maximum range of sensor measurement is 70% of the full range of the sensor. That is to say, to measure the pressure of 70 bar now, we should choose 100 bar for the range of pressure transmitter. Please choose the refined tower product.
Fourth, output signal.
At present, due to various acquisition needs, there are many kinds of pressure transmitter output signals on the market, mainly 4-20 mA, 0-20 mA, 0-10 V, 0-5 V, etc. But the more commonly used are 4-20 mA and 0-10 V. Among the output signals mentioned above, only 4-20 mA is two-wire system (the output system we said is several-wire system without grounding or shielding lines), and the others are three-wire system.
Fifth, medium temperature.
Because the signal of pressure transmitter is partly converted by electronic circuit, the temperature of measuring medium of pressure transmitter is - 30 to + 100 degrees in general. If the temperature is too high, we usually use condensation bending to cool medium. This will reduce the cost of making a high temperature resistant pressure transmitter for you by the manufacturer.
Sixth, measurement medium.
Generally, we measure relatively clean fluids. We can use standard pressure transmitter directly. If the medium you measure is easy to crystallize or sticky, we usually use external diaphragm or chemical seal together. This will effectively prevent the medium from blocking the pressure measurement hole.
After determining the above five parameters, we also need to confirm the process connection interface of your pressure transmitter and the supply voltage of the pressure transmitter; if used in special occasions, we also need to consider explosion-proof and protection level.