Emerson Rosemount 644 with HART Protocol User Manual

76
Reference Manual
00809-0200-4728, Rev SA
Troubleshooting
July 2018
Troubleshooting
6.3 4–20 mA/HART output
Table 6-1. Troubleshooting 4–20 mA Output
Symptom or
issue
Potential
source
Corrective action
Transmitter does
not communicate
with Field
Communicator
Loop wiring
 Check the revision level of the transmitter device descriptors (DDs) stored in
your communicator. The communicator should report Dev v4, DD v1
(improved), or reference “Field Communicator” on page 6 for previous
versions. Contact Emerson
™
Customer Central for assistance.
 Check for a minimum of 250 ohms resistance between the power supply and
Field Communicator connection.
 Check for adequate voltage to the transmitter. If a Field Communicator is
connected and 250 ohms resistance is properly in the loop, then the
transmitter requires a minimum of 12.0 V at the terminals to operate (over
entire 3.5–23.0 mA operating range), and 12.5 V minimum to communicate
digitally.
 Check for intermittent shorts, open circuits, and multiple grounds.
High output
Sensor input
failure or
connection
 Connect a Field Communicator and enter the transmitter test mode to check
for a sensor failure.
 Check for a sensor open or short circuit.
 Check the process variable to see if it is out of range.
Loop wiring
 Check for dirty or defective terminals, interconnecting pins, or receptacles.
Power supply
 Check the output voltage of the power supply at the transmitter terminals. It
should be 12.0–42.4 Vdc (over entire 3.75–23 mA operating range).
Electronics
 Connect a Field Communicator and enter the transmitter status mode to
isolate module failure.
 Connect a Field Communicator and check the sensor limits to ensure
calibration adjustments are within the sensor range.
Erratic output
Loop wiring
 Check for adequate voltage to the transmitter. It should be 12.0–42.4 Vdc at
the transmitter terminals (over entire 3.75–23 mA operating range).
 Check for intermittent shorts, open circuits, and multiple grounds.
 Connect a Field Communicator and enter the Loop test mode to generate
signals of 4 mA, 20 mA, and user-selected values.
Electronics
 Connect a Field Communicator and enter the transmitter test mode to isolate
module failure.

Emerson Rosemount 644 with HART Protocol Specifications

General

Brand	Emerson
Model	Rosemount 644 with HART Protocol
Category	Transmitter
Language	English