ABB MAG-X 3000 Series Instruction Manual page 52

INSTRUCTION MANUAL 10DX3111A&G Sizes 14 - 24 Inches
6.3.2.2 Empty Pipe Test
If possible, the pipeline should now be drained and the flowmeter should be given a few minutes to
allow the fluid to drain off the electrode to liner interface. Connection of either a DC or AC ohmmeter
between electrode terminals "1" or "2" and the meter body (terminal "3") should result in a reading
greater than 5 MΩ. Lower readings indicate either that process fluid has leaked behind the electrode
or that moisture has entered the flowmeter housing. If this is the case, the defective meter should be
returned to the factory for repair.
6.3.2.3 Electrode Voltage Test
If no erroneous readings are found when the electrode resistance test is performed, an additional test
may be performed with the system powered and the field wiring restored. Use a digital voltmeter, with
a range-setting of 20VDC, to measure the voltage between electrode terminals 1 & 3 (common) and
between electrode terminals 2 & 3. The voltage readings should be between +10 mV and +2 VDC and
should not differ by more than 0.4 VDC. If measured voltages are outside of these ranges, it may
indicate that an electrode is open, shorted or that the process fluid is non-conductive.
If the results of the procedures in Sections 6.3.2.1 through 6.3.2.3 indicate normal meter parameters,
the flowmeter may be returned to service.
Refer to the instruction bulletin supplied with the Signal Converter for additional advice on trou-
bleshooting flowmeter electronics.
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