Rosemount 3051 pressure transmitter
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I have a Rosemount 3051 pressure transmitter here. It worked fine after installation, but after some time, it started outputting 22mA even when there was no pressure. I replaced it with another transmitter of the same model, and it functioned well at first as well; however, after some time, it began to output 22mA again even in the absence of pressure. I checked everything – the diaphragm bag was undamaged, and the 24V supply voltage was normal. I also used a Hart communicator to access the transmitter’s internal settings, and communication worked fine. Yet, in the communicator’s display, the pressure value shown internally was clearly 0, but the internal output remained at 22mA. Has anyone else encountered this problem? What could be the cause, and are there any solutions?
You can use the diagnostic menu to check for any error messages
What medium is being measured? What is the range setting of the instrument? What is the common value? Is it often used beyond its range? Or is there an issue with the selection?
Try to disable some alarms and see if the output value is 4mA, or below the alarm threshold set by the instrument
Generally, there are more issues with the alarm settings
If there is a cable fault, simply replace the cable. Since HART is a digital-analog mixed signal, the communicator shows the correct value; however, due to ground leakage in the cable, the loop current becomes abnormal.
What is the measuring medium – a regular pressure gauge or one with a remote transmission diaphragm box? It would be best to provide the model number. Please pay attention to what is displayed on the gauge’s screen; if you give me all the information shown there, I think I can give you a ** answer
Also, the accurate output of this device shouldn’t be 22mA; it’s probably 21.75. This value indicates a hardware fault
If the instrument outputs 22mA, that should be the instrument’s alarm current; so it’s better to first check what the instrument’s alarm messages say. As soon as I picked up the controller, it started working on its own after a while.
Both pressure transmitters were functioning normally before use, but after operating properly for a while they started to have problems; they could communicate but failed to pass the self-check
The medium is steam (condensation measures have been taken; once opened, the transmitter chamber is filled with water, ruling out damage to the diaphragm box). The range is 2.5 MPa, with 0.9–1.0 MPa being the commonly used range. It is not possible to use it beyond this range, as the pressure in the main pipe is only around 1.0 MPa; therefore, there are no issues with the selection