Pressure transmitter issues
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There is a system that needs to be able to operate under both negative and positive pressures (around 0.1 MPa). Should a single pressure transmitter be used, or should separate transmitters be chosen for positive and negative pressures?
Personally, I think choosing one is enough.
Could there be issues with measurement accuracy?
An absolute pressure transmitter will do.
Thank you very much. Additionally, my equipment has pressure transmitters at both the top and bottom; is it still necessary to install a differential pressure gauge? Is it better to just do the calculation directly on the DCS?
If you want to save money, just do the calculations directly; if you’re wealthy and prioritize accuracy, you can use the previous differential pressure transmitter
One transmitter. If the PT operating pressure (normal operating point) is less than 10 KPaA, a gauge pressure transmitter is recommended. If the equipment pressure drop is less than 5 KPa, it is recommended to use a differential pressure transmitter for measurement (by subtracting values in the DCS system; a negative value is often obtained, especially with capillaries, which leads to jokes from process engineers)
If level control is required, it is recommended to add a differential pressure transmitter, as this provides more accurate control.
A gauge pressure transmitter should be used; in our factory, when gauge pressure is used to measure negative pressure environments for an extended period, there can be issues with the lifespan of the diaphragm
It can also be achieved by selecting a table. For example: -0.1~0.1MPa is sufficient