Rosemount 8712, Reference Manual

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Reference Manual
00809-0100-4664, Rev BA
January 2010
6-3
Rosemount 8712
DIAGNOSTIC
MESSAGES
Problems in the magnetic flowmeter system are usually indicated by incorrect
output readings from the system, error messages, or failed tests. Consider all
sources in identifying a problem in your system.
Table 6-1. Rosemount 8712 Basic Diagnostic Messages
Message Potential Cause Corrective Action
“Empty Pipe” Empty Pipe None - message will clear when pipe is full
Wiring Error Check that wiring matches appropriate wiring diagrams - see Appendix E:
Universal Sensor Wiring Diagrams
Electrode Error Perform sensor tests C and D (see Table 6-6 on page 6-9)
Conductivity less than 5
microsiemens per cm Increase Conductivity to greater than or equal to 5 microsiemens per cm
Intermittent Diagnostic Adjust tuning of Empty Pipe parameters
“Coil Open Circuit” Improper wiring Check coil drive wiring and sensor coils
Perform sensor test A - Sensor Coil
Other manufacturer’s sensor Change coil current to 75 mA
Perform a Universal Auto Trim to select the proper coil current
Circuit Board Failure Replace Rosemount 8712 Electronics
Verify the transmitter is not a
Rosemount 8712H Replace Rosemount 8712H with Rosemount 8712C/U/H/D
Coil Circuit OPEN Fuse Return to factory for fuse replacement
“Auto Zero Failure” Flow is not set to zero Force flow to zero, perform autozero
Unshielded cable in use Change wire to shielded cable
Moisture problems See moisture problems in “Accuracy Section”
“Auto-Trim Failure” No flow in pipe while performing
Universal Auto Trim Establish a known flow in tube, and perform Universal Auto-Trim calibration
Wiring error Check that wiring matches appropriate wiring diagrams - see “Universal
Sensor Wiring Diagrams” on page E-1
Flow rate is changing in pipe while
performing Universal Auto-Trim
routine Establish a constant flow in tube, and perform Universal Auto-Trim
calibration
Flow rate through sensor is
significantly different than value
entered during Universal Auto-Trim
routine Verify flow in tube and perform Universal Auto-Trim calibration
Incorrect calibration number
entered into transmitter for
Universal Auto-Trim routine Replace sensor calibration number with 1000005010000001
Wrong tube size selected Correct tube size setting - See “Line Size” on page 3-10
Sensor failure Perform sensor tests C and D (see Table 6-6 on page 6-9)
“Electronics Failure” Electronics self check failure Replace Electronics
“Electronics Temp Fail” Ambient temperature exceeded the
electronics temperature limits Move transmitter to a location with an ambient temperature range of -40 to
165 °F (-40 to 74 °C)
“Reverse Flow” Electrode or coil wires reverse Verify wiring between sensor and transmitter
Flow is reverse Turn ON Reverse Flow Enable to read flow
Sensor installed backwards Re-install sensor correctly, or switch either the electrode wires (18 and 19)
or the coil wires (1 and 2)
“PZR Activated”
(Positive Zero Return)
External voltage applied to
terminals 5 and 6 Remove voltage to turn PZR off
“Pulse Out of Range” The transmitter is trying to
generate a frequency greater than
11,000 Hz Increase pulse scaling to prevent pulse output going above 11,000 Hz
Verify the sensor calibration number is correctly entered in the electronics
“Analog Out of Range” Flow rate is greater than analog
output Range Reduce flow, adjust URV and LRV values
Verify the sensor calibration number is correctly entered in the electronics