15.11 Checking Process Variables And Test Points - Emerson Micro Motion 3711 Configuration And Use Manual

Maintenance and Troubleshooting
Table 15-1 Status alarms and remedies continued
Alarm
code Message
NA Amplitude Mismatch
NA Pickoff 180 Out of
Phase
NA Pickoff Frequency Out of
Range

15.11 Checking process variables and test points

Micro Motion suggests that you make a record of the variables and test points listed below, under
normal operating conditions. This will help you recognize when the values are unusually high or low.
• Flow rate
• Density
• Temperature
• Delta T
• Tube frequency
• Tube period
• Pickoff voltage
• Drive gain
• Tube temperature
• Core temperature
• Core input voltage
The first three can be read from a number of locations in ROCLINK 800. To read the last eight, use
the User Registers panel (see Section 13.5) with the register data shown in Table 15-2.
Table 15-2 Modbus register data for operating variables
Process variable
Delta T
Tube frequency
Tube period
Left pickoff voltage
Right pickoff voltage
Drive gain
Tube temperature
Core temperature
Core input voltage
For troubleshooting, check the variables under both normal flow and tubes-full no-flow conditions.
Unusual values for these variables may indicate a variety of different problems. Table 15-3 lists
several possible problems and remedies.
176
Possible remedy
Contact Micro Motion. See Section 1.8.
Contact Micro Motion. See Section 1.8.
Contact Micro Motion. See Section 1.8.
Register #
387
369
285
379
381
291
371
383
385
Data type
Float
Float
Float
Float
Float
Float
Float
Float
Float
®
Micro Motion Model 3711 Gas Flow Computers