Emerson Rosemount 644, Reference Manual

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79
Reference Manual
00809-0200-4728, Rev RA
Section 6: Troubleshooting
April 2015
Troubleshooting
Low or No
Output
Sensor
Element

Connect a Field Communicator and enter the transmitter test mode to isolate
a sensor failure.

Check the process variable to see if it is out of range.
Loop
Wiring

Check for adequate voltage to the transmitter. It should be 12.0 to 42.4 Vdc
(over entire 3.75 to 23 mA operating range).

Check for shorts and multiple grounds.

Check for proper polarity at the signal terminal.

Check the loop impedance.

Connect a Field Communicator and enter the Loop test mode.

Check wire insulation to detect possible shorts to ground.
Electronics

Connect a Field Communicator and check the sensor limits to ensure
calibration adjustments are within the sensor range.
Table 6-1. Rosemount 644 Troubleshooting Table for 4-20 mA Output
Symptom or
issue Potential
source
Corrective action