Troubleshooting

11.13Checking process variables

Micro Motion suggests that you make a record of the process variables listed below, under normal operating conditions. This will help you recognize when the process variables are unusually high or low.

Flow rate

Density

Temperature

Tube frequency

Pickoff voltage

Drive gain

To view these values:

With ProLink II, use the Status window and the Diagnostic Information window. Both of these windows are opened from the ProLink menu.

Using the display, you must configure the display to show them. See Section 8.9.5.

Using a DeviceNet tool, see Tables C-1through C-5and Table C-7.

For troubleshooting, check the process variables under both normal flow and tubes-full no-flow conditions. Except for flow rate, you should see little or no change between flow and no-flow conditions. If you see a significant difference, record the values and contact Micro Motion customer service for assistance. See Section 11.3.

Unusual values for process variables may indicate a variety of different problems. Table 11-3lists several possible problems and suggested remedies.

Table 11-3Process variables problems and remedies

Symptom

Cause

Suggested remedy

 

 

 

Steady non-zero flow rate under

Misaligned piping (especially in new

• Correct the piping.

no-flow conditions

installations)

 

 

 

 

 

Open or leaking valve

• Check or correct the valve

 

 

mechanism.

 

 

 

 

Bad sensor zero

• Rezero the flowmeter or restore the

 

 

factory zero or prior zero. See

 

 

Section 10.5.

 

 

 

Compensation

Measurement Performance

Troubleshooting

Defaults

Configuration and Use Manual

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Emerson Process Management 2400S manual Checking process variables, 3Process variables problems and remedies