Range selection for differential pressure transmitters when measuring slight negative pressures
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On site, there is an EJA differential pressure transmitter connected via a three-valve manifold; the positive pressure side is connected to the furnace, while the negative pressure side is connected to the atmosphere. This setup is used to measure the slight negative pressure in the furnace chamber (around 80 Pa). Both the DCS range and the gauge’s range cover values from -1000 to 500 Pa. Both the positive and negative pressure chambers are connected to the atmosphere, resulting in a reading of -3 Pa on the gauge, while the DCS shows a value of over 100 Pa. I would like to ask, under normal conditions, how to zero and set the range of the differential pressure gauge for the positive and negative pressure chambers. How is the zero point and range of this EJA gauge calibrated? Thank you so much!
Regarding this issue, we can provide the following suggestions and answers: 1. First, it is necessary to confirm the specifications and measurement range of the differential pressure transmitter to determine whether it is suitable for measuring a slight negative pressure of around 80 Pa. If in doubt, you can refer to the differential pressure transmitter’s manual or consult the manufacturer or distributor. 2. The zero and range adjustment of differential pressure transmitters generally needs to be carried out under pressure-free conditions. For specific adjustment methods, refer to the instructions or consult the manufacturer or distributor. 3. In practical use, the appropriate range can be selected according to the measurement requirements. Under normal circumstances, the range should be greater than the absolute value of the measured value to ensure measurement accuracy and stability. In this case, the range of the differential pressure transmitter can first be set to -1000 to 500 Pa, after which real-time measurements can be taken; the range can then be adjusted based on the results of those measurements. 4. If the differential pressure transmitter frequently experiences issues such as zero drift or unstable range, more detailed inspection and maintenance may be required, including checking the wiring, cleaning the sensor, and replacing the acrylic plate. In this case, it is recommended to seek professional technical support or repair services. .
This post was last edited by jlshnlhj on 2023-4-2 at 17:38: \"Both the positive and negative pressure chambers are connected, showing -3 Pa with respect to atmospheric pressure; the DCS shows over 100 Pa.\" " 1. At the transmitter side, measure the output current of the transmitter and verify whether the current corresponds to -3 Pa 2. At the I/O cabinet in the machine room, measure the current at the input terminal of the DCS card, and verify whether the current corresponds to over 100 Pa Measuring these two currents is the general solution for determining such problems. The input terminal of the DCS card is a dividing point, which allows it to be determined whether the problem lies before or after the input terminal of the DCS card.