Emerson Micro Motion 3711, Руководство по конфигурации и использованию, Страница: 190 / 234

182 Micro Motion
®
Model 3711 Gas Flow Computers
Maintenance and Troubleshooting
15.16.3 Low pickoff voltage
Low pickoff voltage can be caused by several problems. See Table 15-6.
15.17 Checking the core processor
Two core processor procedures are available:
• You can check the core processor LED. The core processor has an LED that indicates different
meter conditions. See Table 15-7.
• You can perform the core processor resistance test to check for a damaged core processor.
15.17.1 Checking the core processor LED
To check the core processor LED:
1. Maintain power to the Model 3711.
2. Remove the core processor lid. The core processor is instrinsically safe and can be opened in
all environments.
Drive board or module failure, cracked flow tube,
or sensor imbalance Contact Micro Motion. See Section 1.8.
Mechanical binding at sensor Ensure sensor is free to vibrate.
Open drive or left pickoff sensor pin Contact Micro Motion. See Section 1.8.
Flow rate out of range Ensure that flow rate is within sensor limits.
Wrong K1 and FCF characterization constants
for sensor Re-enter the K1 and FCF characterization constants. See
Section 5.5.1.
Incorrect sensor type configured Verify sensor characterization. See Section 5.5.1.
Polarity of pick-off reversed or polarity of drive
reversed Contact Micro Motion. See Section 1.8.
Table 15-6 Low pickoff voltage causes and remedies
Cause Possible remedy
Faulty wiring runs between the sensor and core processor Verify wiring. Refer to Appendix A for diagrams, and see
your transmitter installation manual.
Process flow rate beyond the limits of the sensor Verify that the process flow rate is not out of range of the
sensor.
Slug flow See Section 15.12.
No tube vibration in sensor Check for plugging.
Ensure sensor is free to vibrate (no mechanical binding).
Verify wiring.
Test pins at sensor. See Section 15.17.
Moisture in the sensor electronics Eliminate the moisture in the sensor electronics.
The sensor is damaged Contact Micro Motion. See Section 1.8.
Table 15-5 Drive gain problems, causes, and remedies
Cause Possible remedy