Emerson Rosemount 644 Reference Manual page 89

Reference Manual
00809-0200-4728, Rev RA
Table 6-1. Rosemount 644 Troubleshooting Table for 4-20 mA Output
Symptom or Potential
issue source
Sensor
Element
Low or No
Loop
Output
Wiring
Electronics
Troubleshooting
Corrective action
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.

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.

Connect a Field Communicator and check the sensor limits to ensure

calibration adjustments are within the sensor range.
Section 6: Troubleshooting
April 2015
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