Table 5-4: Unexpected Process Variable (PV) Readings (continued)
Symptom Corrective action
• Adjust the damping.
Feature board electronics
• Connect a personal computer and use AMS Device Manager,
Engineering Assistant Software, or the Field Communicator to check
the sensor limits to ensure calibration adjustments are within the
sensor range and that calibration is correct for the pressure being
applied.
• Confirm the electronics housing is properly sealed against moisture.
• If the feature board electronics are still not functioning properly,
substitute new feature board electronics.
Impulse piping
• Check for entrapped gas in liquid lines or for liquid in gas lines.
• Make sure that process fluid has not frozen within the process flange.
• Ensure that block valves are fully open and equalize valves are fully
and tightly closed.
Sensor module
• The sensor module is not field repairable and must be replaced if
found to be defective. Check for obvious defects, such as a punctured
isolating diaphragm or fill fluid loss, and contact your nearest
Emerson Service Center.
Low PV Reading or No
PV Reading
Primary element
• Check the installation and condition of the primary element. Note any
changes in process fluid properties that may affect output.
Loop wiring
• Check for adequate voltage to the transmitter. It should be 12 to 42.4
Vdc for HART with no load at the transmitter terminals.
• Check the milliamp rating of the power supply against the total
current being drawn for all transmitters being powered.
• Check for shorts and multiple grounds.
• Check for proper polarity at the signal terminal.
• Check loop impedance.
• Check the wire insulation to detect possible shorts to ground.
Impulse piping
• Check to ensure the pressure connection is correct.
• Check for leaks or blockage.
• Check to ensure blocking valves are fully open and that bypass valves
are tightly closed.
• Check for entrapped gas in liquid lines or for liquid in gas lines.
• Check for sediment in the transmitter process flange.
• Make sure process fluid has not frozen within the process flange.
Symptom Corrective action
Reference Manual Troubleshooting
00809-0100-4803 October 2018
Emerson.com/Rosemount 139
To Next Page
Loading...
