Summary of ROSEMENT differential pressure transmitter issues

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Summary of common problems with Rosemount differential and gauge pressure transmitters – Simple issues that often occur with these transmitters in the field:
1. The operator panel is in English, so users generally don’t even look at it.
2. Users don’t know how to perform basic operations using the operator panel.
3. Poor wiring by users results in zero current in the circuit.
4. Communication problems.
5. For level transmitters, proper handling of the filling fluid in the pressure transduction tubes.
6. Correct calibration of remote transmitters.
7. Use of valve assemblies.
8. On-site zeroing.

I. Regarding the English-language operator panel: Inform users about the first screen that appears after the panel enters communication mode.
II. What do the shortcut key codes mean? There’s an operation guide included with the instrument, which outlines these codes; knowing how to use them is sufficient.
III. When users report no output or communication issues, it’s necessary to ask for specific details such as the current value. If there’s no current, check the circuit by measuring the voltage across the instrument.
IV. When the instrument cannot communicate, ask the user whether the supply voltage is normal, what the circuit current is, and whether a 250-ohm resistor is installed in the circuit.
V. For level transmitters, since pressure transduction tubes are installed at both the low-pressure and high-pressure ends, there must be no air in these tubes. There should also be no U-shaped sections in the lower end of the tubes. Reason: If the liquid level is below the pressure transduction tube, the liquid will flow back, causing air to accumulate inside the tube. Changes in pressure within the tube will then cause changes in the liquid level displayed by the transmitter.
VI. For remote transmitters with dual capillaries, if users report inaccurate measurements, ask whether they have calibrated the transmitter according to requirements and whether they have adjusted the zero point. If calibration hasn’t been done, press the zero button for 5 seconds when the liquid level is at zero. The measurement range is determined by adding the liquid level height multiplied by the specific gravity to the zero point.
VII. When using a three-valve assembly, both sides should be open during operation, with the middle valve closed. For a five-valve assembly, both sides are open while all other valves are closed. To zero the instrument, open the balance valve in the middle of the three-valve assembly and close the high-pressure valve. In the five-valve assembly, close the topmost valve and the high-pressure valve, while keeping the two middle valves open.
VIII. Zeroing includes adjusting the transmitters for atmospheric pressure, as well as setting the zero point when atmospheric pressure isn’t used as the reference. The former can be done using the operator panel, for example via the 12331 shortcut key. The latter requires using the instrument’s built-in zeroing function; press Z for 5 seconds once it’s confirmed that the zero point is correct on site