Hello,
We recently had a 3051 gauge pressure transmitter decide to change its range in the middle of the night. The desired range and calibrated range is 0-1000 psig. Typical operating pressure is ~300 psig. A couple of nights ago, this transmitter decided to change its URV from 1000 to 315.7. The tranmitter display indicated the proper pressure and the milliamp output calculated to be accurate at this range, but it was throwing our DCS control off. The output was 19.1 mA as found. I changed the URV back to 1000 and this fixed the issue. Can anyone explain to me how this transmitter decided to change its URV in the middle of the night? The ambient temp was about 100°F. There was nobody in the area that would have changed the range and the cameras back that up. The transmitter is not on a HART AI for the DCS, so I don't think there could be any input from the DCS that would affect it.