Emerson Micro Motion 3711, Configuration And Use Manual, Page: 184 / 234

176 Micro Motion
®
Model 3711 Gas Flow Computers
Maintenance and Troubleshooting
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.
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.
NA Amplitude Mismatch Contact Micro Motion. See Section 1.8.
NA Pickoff 180 Out of
Phase Contact Micro Motion. See Section 1.8.
NA Pickoff Frequency Out of
Range Contact Micro Motion. See Section 1.8.
Table 15-2 Modbus register data for operating variables
Process variable Register # Data type
Delta T 387 Float
Tube frequency 369 Float
Tube period 285 Float
Left pickoff voltage 379 Float
Right pickoff voltage 381 Float
Drive gain 291 Float
Tube temperature 371 Float
Core temperature 383 Float
Core input voltage 385 Float
Table 15-1 Status alarms and remedies continued
Alarm
code
Message Possible remedy