Troubleshooting
11.21Checking the characterization
A transmitter that is incorrectly characterized for its sensor might produce inaccurate output values. If the flowmeter appears to be operating correctly but sends inaccurate output values, an incorrect characterization could be the cause.
If you discover that any of the characterization data are wrong, perform a complete characterization. See Section 4.2.
11.22Checking the calibration
Improper calibration can cause the transmitter to send unexpected output values. If the transmitter appears to be operating correctly but sends inaccurate output values, an improper calibration may be the cause.
Micro Motion calibrates every transmitter at the factory. Therefore, you should suspect improper calibration only if the transmitter has been calibrated after it was shipped from the factory.
The calibration procedures in this manual are designed for calibration to a regulatory standard. See Chapter 10. To calibrate for true accuracy, always use a measurement source that is more accurate than the meter. Contact Micro Motion customer service for assistance.
Note: Micro Motion recommends using meter factors, rather than calibration, to prove the meter against a regulatory standard or to correct measurement error. Contact Micro Motion before calibrating your flowmeter. For information on meter performance, see Chapter 10.
11.23Checking the test points
Some status alarms that indicate a sensor failure or overrange condition can be caused by problems other than a failed sensor. You can diagnose sensor failure or overrange status alarms by checking the meter test points. The test points include left and right pickoff voltages, drive gain, and tube frequency. These values describe the current operation of the sensor.
11.23.1Obtaining the test points
To obtain the test points with ProLink II software:
1.Select Diagnostic Information from the ProLink menu.
2.Write down the values you find in the Tube Frequency box, the Left Pickoff box, the Right Pickoff box, and the Drive Gain box.
11.23.2Evaluating the test points
Use the following guidelines to evaluate the test points:
•If the drive gain is unstable, refer to Section 11.23.3.
•If the value for the left or right pickoff does not equal the appropriate value from Table
•If the values for the left and right pickoffs equal the appropriate values from Table
Compensation
Measurement Performance
Troubleshooting
Defaults
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