Rosemount Model 8712C/U/H Magnetic Flowmeter Transmitters
3-4
DIAGNOSTIC MESSAGES
The following error messages may appear on the LOI screen. To correct
the problem, complete the steps indicated. If the problem persists,
contact your sales or service representative. A letter “R” representing
reverse flow and a letter “T” representing totalizer will flash on the LOI
when activated.
TABLE 3-2. LOI Error Messages
Symptom Potential Cause Corrective Action
“Empty Pipe” displayed Empty pipe None – message will clear when pipe is full
Wiring error Check that wiring matches appropriate wiring
diagrams – see Appendix B
Electrode failure Perform flowtube tests C and D on page 5-6
Conductivity less than 5 microhms per cm Increase conductivity to ≥ 5 microhms per cm
Damaged or shorted transmitter to flowtube
cables
Replace transmitter to flowtube cables
Coil Drive Open Circuit Displayed Improper wiring Check coil drive wiring and flowtube coils
Perform flowtube test A–Flowtube Coil (see
page 5-6)
Other manufacturer’s flowtube Change coil current to 75 mA
Electronics failure Replace Model 8712C/U/H electronics
Verify the transmitter is
not
a Model 8712H Replace Model 8712H with Model 8712C/U/H
Flowtube will not Autozero
(“Autozero Failure” can be cleared by
cycling power)
Flow is not set to zero Force flow to zero, re-perform autozero
Unshielded cable in use Change wire to shielded cable
Moisture problems See moisture problems in “Accuracy Section”
LOI is blank Model 8712C/U/H is ranged improperly
4 mA point = 20 mA point
Correct ranging with HART Communicator –
see URV (Upper Range Value) on page 4-6
and LRV (Lower Range Value) on page 4-7
Blown fuse Check fuse and replace with an appropriately
rated fuse, if necessary
LOI failure Replace LOI
Electronics failure Replace electronics – see Replacing the
Electronics Module on page 5-7
LOI is blinking, scrolling, or displaying
scrambled letters
Unit experienced large transient Recycle power – if problem persists replace
electronics
LOI does not respond to key press LOI failure Replace LOI – use the HART Communicator in
the interim
Electronics failure Replace the electronics – see Replacing the
Electronics Module on page 5-7
“Auto-trim Failure” displayed
(Transmitter power must be cycled to clear
error message)
No flow in pipe while performing universal
auto trim
Establishaknownflowintube,andperform
universal auto-trim calibration – see Universal
Auto Trim (Model 8712U Only) on page 4-5
Wiring error or floating electrode shield Check that wiring matches appropriate wiring
diagrams – see Appendix B
Flow rate is changing in pipe while performing
universal auto trim routine
Establish a constant flow in tube, and perform
universal auto-trim calibration – see Universal
Auto Trim (Model 8712U Only) on page 4-5
Flow rate through flowtube is significantly
different than value entered during universal
auto trim routine
Verify flow in tube and perform universal auto-
trim calibration – see Universal Auto Trim
(Model 8712U Only) on page 4-5
Incorrect flowtube calibration number entered
into transmitter for universal auto trim routine
Replace flowtube calibration number with
1000005010000001 – see Calibration
Number on page 4-8
Wrong tube size selected Correct tube size setting – see Line Size on
page 4-7
Flowtube failure Perform flowtube tests C and D on page 5-6
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