Pressure transmitter selection basis

1. What kind of pressure should the transmitter measure? First determine the maximum value of the measured pressure in the system. Generally speaking, you need to select a transmitter with a pressure range that is about 1.5 times larger than the maximum value. This is mainly because in many systems, especially in water pressure measurement and processing, there are peaks and continuous irregular up and down fluctuations. Such instantaneous peaks can destroy the pressure sensor. 1. What kind of pressure should the transmitter measure? First determine the maximum value of the measured pressure in the system. Generally speaking, you need to select a transmitter with a pressure range that is about 1.5 times larger than the maximum value. This is mainly because in many systems, especially in water pressure measurement and processing, there are peaks and continuous irregular up and down fluctuations. Such instantaneous peaks can destroy the pressure sensor. Continuously high pressure values u200bu200bor slightly exceeding the maximum value of the transmitter's calibration will shorten the life of the sensor, and doing so will also reduce the accuracy. So a buffer can be used to reduce the pressure glitch, but this will reduce the response speed of the sensor. Therefore, the pressure range, accuracy and stability should be fully considered when selecting a transmitter. 2. What kind of pressure medium, viscous liquid or mud, will block the pressure interface, and will the solvent or corrosive substances destroy the materials in the transmitter that are in direct contact with these media. The above factors will determine whether to choose a direct isolation membrane and a material in direct contact with the medium. 3. How much accuracy the transmitter needs determines the accuracy, such as non-linearity, hysteresis, non-repeatability, temperature, zero offset scale, and temperature. But it is mainly caused by non-linearity, hysteresis, and non-repeatability. The higher the accuracy, the higher the price. 4. The temperature range of the transmitter. Generally, a transmitter will calibrate two temperature ranges, one of which is the normal working temperature, and the other is the temperature compensation range. The normal working temperature range refers to the working condition of the transmitter. The temperature range when it is not destroyed may not reach the performance index of its application when it exceeds the temperature compensation range. The temperature compensation range is a typical range smaller than the operating temperature range. Working within this range, the transmitter will definitely achieve its due performance indicators. The temperature change affects its output from two aspects, one is the zero drift, and the other is the full-scale output. For example: +/-X%/℃ of full scale, +/-X%/℃ of reading, +/-X% of full scale when out of temperature range, +/-X% of reading when in temperature compensation range Without these parameters, it will lead to uncertainty in use. The change in the output of the transmitter is caused by pressure changes or temperature changes. Temperature effects are the most complicated part of understanding how to use a transmitter. 5. What kind of output signal mV, V, mA and frequency output digital output need to be obtained, and the choice of output depends on many factors, including the distance between the transmitter and the system controller or display, whether there is 'noise' or other Electronic interference signal, whether an amplifier is needed, the position of the amplifier, etc. For many OEM devices with a short distance between the transmitter and the controller, the mA output transmitter is the most economical and effective solution. If you need to amplify the output signal, it is best to use a transmitter with built-in amplification. For long-distance transmission or strong electronic interference signals, it is best to use mA-level output or frequency output. If you are in an environment with high RFI or EMI indicators, in addition to choosing mA or frequency output, you must also consider special protection or filters. 6. What kind of excitation voltage to choose. The type of output signal of SBW series flameproof and intrinsically safe temperature transmitters with thermocouple (resistance) determines the choice of excitation voltage. Many transmitters have built-in voltage regulators, so their power supply voltage range is relatively large. Some transmitters are quantitatively configured and require a stable operating voltage. Therefore, the operating voltage determines whether to use a sensor with a regulator. When selecting a transmitter, the operating voltage and system cost should be considered comprehensively.　　7. Do you need an interchangeable transmitter?