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In terms of their names alone, pressure transmitters and differential transmitters measure pressure and the difference between two pressures, but there are many parameters that they indirectly measure. Like pressure transmitters, in addition to measuring pressure, they can also measure the liquid level inside a device. When measuring liquid level in a container at atmospheric pressure, only a pressure transducer is required. When measuring the liquid level in a pressurized container, two pressure transducers can be used – one to measure the lower limit and another to measure the upper limit. By performing a subtraction operation on their output signals, it is possible to determine the liquid level; this approach is commonly employed. It can also be used to measure the density of the medium when the liquid level and pressure values inside the container remain constant. The measurement range of pressure transmitters can be very wide, ranging from 0 absolute pressure up to 100 MPa. 1. Transmitter range First, determine the maximum pressure value to be measured in the system; generally, it is necessary to choose a transmitter with a pressure range that is about 1.5 times larger than this maximum value. This is mainly because in many systems, especially those involved in pressure measurement and processing, there are peak values as well as continuous irregular fluctuations; such sudden peaks can damage pressure sensors. Sustained high pressure levels or values slightly above the transmitter’s calibrated maximum can shorten the sensor’s lifespan, and it also leads to a decrease in accuracy. Therefore, a buffer can be used to reduce pressure spikes, but this will decrease the sensor’s response speed. Therefore, when selecting a transmitter, the pressure range, accuracy, and stability must be taken into full consideration. 2. Media detected by pressure transmitters Viscous liquids and mud can clog the pressure interface, while solvents or corrosive substances may damage the materials in the transmitter that come into direct contact with these media. These factors will determine whether to choose a direct isolation film and materials in direct contact with the dielectric. 3. Transmitter accuracy Factors that determine accuracy include non-linearity, hysteresis, non-repeatability, temperature, zero offset scaling, and the influence of temperature. But due mainly to non-linearity, hysteresis, and non-repeatability, the higher the precision, the higher the price. 4. Temperature range of the transmitter Typically, a transmitter is calibrated for two temperature ranges: one is the normal operating temperature, and the other is the temperature compensation range. The normal operating temperature range refers to the temperature range within which the transmitter can function without being damaged; outside this temperature compensation range, it may fail to meet the required performance specifications. The temperature compensation range is a typical range that is smaller than the operating temperature range. Operating the transmitter within this range will definitely ensure that it meets its specified performance criteria. Temperature affects its output in two ways: one is zero drift, and the other is an impact on the full-scale output. For example: +/-X%/℃ of full scale, +/-X%/℃ of the reading, +/-X% of full scale when outside the temperature range, +/-X% of the reading within the temperature compensation range; the absence of such parameters leads to uncertainty in use. The change in the transmitter output is caused by pressure changes or by temperature changes. The effect of temperature is the most complex part when understanding how to use transmitters. 5. Output signal of the pressure transmitter: mV, V, mA, and digital output at frequency. The choice of output depends on various factors, including the distance between the transmitter and the system controller or display, the presence of \"noise\" or other electronic interference signals, whether an amplifier is needed, and the location of the amplifier. For OEM devices where the distance between many transmitters and controllers is short, transmitters with mA output represent the most economical and effective solution. If it is necessary to amplify the output signal, it is best to use a transmitter with built-in amplification. For long-distance transmission or in the presence of strong electronic interference signals, it is best to use mA-level output or frequency output. In environments with high RFI or EMI levels, in addition to choosing mA or frequency output, it is also necessary to consider special protection measures or filters. 6. Connection methods between the transmitter and other electronic devices: threaded connection, flange connection. Is a short-distance connection necessary? If a long-distance connection is used, is a connector required? 7. Transmitter Enclosure The enclosure of pressure transmitters often involves ignoring their frame, yet this aspect will gradually reveal its disadvantages during subsequent use. When selecting a transmitter, it is essential to take into account the future operating environment of the transmitter, such as the level of humidity, how it will be installed, and whether there will be any severe impacts or vibrations. These are the parameters we need to be aware of when selecting pressure transmitters. For more information, please visit the company’s official website at http://www.yb1518.com/. 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