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How to Select Pressure Transmitter |
1. What kind of pressure should the transmitter measure? To determine the maximum measurement pressure in the system, only a transmitter with a pressure range about 1.5 times larger than the maximum is needed. This is mainly because in many systems, especially in water pressure measurement and processing, there are peaks and continuous irregular fluctuations, which can destroy the pressure sensor. Continuous high pressure or slightly exceeding the maximum calibration value of the transmitter will shorten the life of the sensor, which will also reduce the accuracy. A buffer can then be used to reduce the pressure burr, but this reduces the response speed of the sensor. Therefore, the pressure range, accuracy and stability should be fully considered when choosing the transmitter. 2. Temperature range of transmitter Usually a transmitter will calibrate two temperature definite sections, one of which is the normal working temperature, the other is the temperature compensation range. The normal working temperature range refers to the temperature range of the transmitter when it is not destroyed under the working condition, and 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 working temperature range. In this range, the transmitter will certainly achieve its due performance. Temperature affects its output from two aspects: zero drift and full range output. For example: full range +/-X%/(?), reading +/-X%/(?), full range +/-X% beyond the temperature range, and reading +/-X% within the temperature compensation range. Without these parameters, it will lead to uncertainty in use. Is the change of transmitter output caused by the change of pressure or by the change of temperature? Temperature effects are the most complex part of understanding how to use transducers. 3. What kind of pressure medium Viscous liquids and mud will plug the pressure interface. Will solvents or corrosive substances destroy the materials directly contacted with these media in the pressure transmitter? These factors will determine whether to choose a direct isolation film and materials in direct contact with the medium. 4. How Precision Transmitter Needs The accuracy is determined by non-linearity, hysteresis, non-repeatability, temperature, zero offset calibration, and temperature effect. But mainly by non-linearity, hysteresis, non-repeatability, the higher the accuracy, the higher the price. 5. Pressure transmitter needs to maintain stability after overtime operation Most transmitters will drift after overworking, so it is necessary to know the stability of the transmitter before purchasing. This kind of advance work can reduce the troubles in future use. 6. Packaging of Transmitter The encapsulation of the transmitter is often neglected as its frame, but this will gradually expose its shortcomings in future use. When choosing the transmitter, we must consider the working environment, humidity, how to install the transmitter, whether there will be strong impact or vibration, etc. 7. How to Connect Transmitter with Other Electronic Equipment Do you need to use a short distance connection? If you use a long distance connection, do you need to use a connector? 8. What kind of output signal do you need? The choice of digital output of mV, V, mA and frequency output depends on a variety of factors, including the distance between transmitter and system controller or display, the existence of "noise" or other electronic interference signals, the need for amplifiers, the location of amplifiers, etc. For many OEM devices with short distance between transmitters and controllers, the pressure transmitter with mA output is the most economical and effective solution. If the output signal needs to be amplified, it is better to use a transmitter with built-in amplification. For long-distance transmission or strong electronic interference signal, it is better to use mA output or frequency output. If you are in an environment with high RFI or EMI indicators, you should not only pay attention to the choice of mA or frequency output, but also consider special protection or filters. 9. How to Choose Excitation Voltage The type of output signal determines the excitation voltage to be selected. Many transmitters have built-in voltage regulators, so their power supply voltage range is large. Some transmitters are quantitatively configured and need a stable working voltage. Therefore, the working voltage decides whether to use a sensor with a regulator or or not. When choosing a transmitter, the working voltage and system cost should be considered comprehensively. 10. Need an interchangeable transmitter Determine whether the required pressure transmitter can be adapted to multiple use systems. Generally speaking, this is very important, especially for OEM products. Once the product is delivered to the customer, the cost of calibration is considerable. If the product has good interchangeability, the effect of the whole system will not be affected even if the transmitter used is changed. Notes: RFI: Radio Frequency Interference EMI: EMI
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