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Configuration and Use Manual 109
Troubleshooting
Measurement Performance DefaultsTroubleshootingCompensation
11.24.2 Core processor resistance test
To perform the core processor resistance test:
1. Power down the transmitter.
2. Remove the core processor lid.
3. Disconnect the 4-wire cable between the core processor and the transmitter (see Figure B-3 or
Figure B-4).
4. Measure the resistance between core processor terminals 3 and 4 (RS-485/A and RS-485/B).
See Figure 11-1. Resistance should be 40 kΩ to 50 kΩ.
5. Measure the resistance between core processor terminals 2 and 3 (VDC– and RS-485/A).
Resistance should be 20 kΩ to 25 kΩ.
6. Measure the resistance between core processor terminals 2 and 4 (VDC– and RS-485/B).
Resistance should be 20 kΩ to 25 kΩ.
7. If any resistance measurements are lower than specified, the core processor may not be able to
communicate with a transmitter or a remote host. Contact Micro Motion (see Section 1.8).
Table 11-12 Enhanced core processor LED behavior, meter conditions, and remedies
LED behavior Condition Possible remedy
Solid green Normal operation No action required.
Flashing yellow Zero in progress If calibration is in progress, no action required. If no calibration is in
progress, contact Micro Motion. See Section 1.8.
Solid yellow Low severity alarm Check alarm status.
Solid red High severity alarm Check alarm status.
Flashing red (80% on,
20% off)
Tubes not full If alarm A105 (slug flow) is active, see Section 11.17.
If alarm A033 (tubes not full) is active, verify process. Check for air in
the flow tubes, tubes not filled, foreign material in tubes, or coating in
tubes.
Flashing red (50% on,
50% off)
Electronics failed Contact Micro Motion. See Section 1.8.
Flashing red (50% on,
50% off, skips every
4th)
Sensor failed Contact Micro Motion. See Section 1.8.
OFF Core processor
receiving less than 5
volts
• Verify power supply wiring to core processor
. Refer to Appendix B for
diagrams.
• If transmitter status LED is lit, transmitter is receiving power. Check
voltage across terminals 1 (VDC+) and 2 (VDC–) in core processor.
If reading is less than 1 VDC, verify power supply wiring to core
processor. Wires may be switched. See Section 11.14.1, and refer to
Appendix B for diagrams. Otherwise, contact Micro Motion (see
Section 1.8).
• If transmitter status LED is not lit, transmitter is not receiving power.
Check power supply. See Section 11.14.1, and refer to Appendix B
for diagrams. If power supply is operational, internal transmitter,
display, or LED failure is possible. Contact Micro Motion. See
Section 1.8.
Core processor
internal failure
Contact Micro Motion. See Section 1.8.