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77
Reference Manual
00809-0200-4728, Rev SA
Troubleshooting
July 2018
Troubleshooting
6.4
Diagnostic messages
Listed in the below sections are detailed tables of the possible messages that will appear on either the
LCD/LOI Display, a Field Communicator, or an AMS Device Manager system. Use the tables below to
diagnose particular status messages.
Failed
Maintenance
Advisory
6.4.1
Failed status
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 12.0–42.4 Vdc
(over entire 3.75–23 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 6-2. Failed – Fix Now
Alert name
LCD screen
LOI screen
Problem
Recommended action
Electronics failure
ALARM
DEVICE
ALARM
FAIL
ALARM
DEVICE
ALARM
FAIL
If diagnostics indicate and
electronics failure, essential
electronics in the device have
failed. For example, the
transmitter may have
experienced an electronics
failure while attempting to
store information.
1. Restart the transmitter.
2. If condition persists, replace the transmitter.
Contact the nearest Emerson Field Service
Center if necessary.
Sensor open
(1)
ALARM
SNSR 1
ALARM
FAIL
ALARM
SNSR 1
ALARM
FAIL
This message indicates that
the transmitter has detected
an open sensor condition. The
sensor may be disconnected,
connected improperly, or
malfunctioning.
1. Verify the sensor connection and wiring.
Refer to the wiring diagrams found on the
transmitter label to ensure proper wiring.
2. Verify the integrity of the sensor and sensor
lead wires. If the sensor is faulty, repair or
replace the sensor.
Table 6-1. Troubleshooting 4–20 mA Output
Symptom or
issue
Potential
source
Corrective action
Summary of Contents for Rosemount 644 with HART Protocol
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