The pressure transmitter keeps dropping after being zeroed at the site
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We checked it ourselves at the office, and when the customer took it back, it kept dropping in value after being zeroed out – from 4.00 to 3.2. And this happened not with just one unit, but with four of them. What could be the problem at the customer’s site?
What the poster means is: after zeroing the pressure transmitter without applying pressure, does the output current drop from 4mA to 3.2mA?
I took it back and left it there for a night; the reading was stable at midnight, and the customer didn’t understand why either
There are two possibilities: either there is a problem with the quality of the transmitter, or the customer is using it improperly on-site.
The situation on site is too complex; anything can happen. Switch to another gauge and use it there – if problems arise again, it will be due to issues with the operating conditions
I’m a user who uses Fuji products; this issue has occurred with three of my instruments. The manufacturer explained that the differential pressure settings at the time of production were determined by the design team, and that after installation we would adjust the range based on the actual conditions on site, which might cause a shift in the zero point. That seems rather far-fetched. Provide a method for us to perform mechanical zeroing by ourselves.
With 4 watches at the same time, it comes down to the common components; if they’re on the same card, try changing the channel.
If zero point calibration is being performed online at the site, a pressure of 0 is required. If calibration is done online without removing the valve, it’s possible that the pressure rises due to the valve not being able to close completely; you can ask what the pressure measured at the site is. If the pressure increase after zeroing is consistently due to a leak inside the valve, it could also be caused by dirt on the diaphragm during on-site measurements, which leads to deformation of the diaphragm. It returned to normal once it was understood