Rosemount 8712C - Basic Transmitter Troubleshooting

Model 8712C/U/H Magnetic Flowmeter Transmitters
5-2
BASIC TRANSMITTER
TROUBLESHOOTING
TABLE 5-1. Basic Troubleshooting–Model 8712C/U/H
Symptom Potential Cause
Corrective Action
Output at 0 mA No power to transmitter Check power source and connections to the transmitter
Blown fuse Check the fuse and replace with an appropriately rated fuse, if necessary
Electronics failure Replace the electronics boards – see Replacing the
Electronics Module on page 5-7
Bad transformer Replace transformer
Analog output improperly
configured
Check the analog power jumper – see Hardware Jumpers/Switches on
page 2-4 for proper settings
Output at 4 mA Open coil drive circuit Check coil drive circuit connections at the flowtube and at the transmitter
Transmitter in multidrop mode Configure Poll Address to 0 to take transmitter out of multidrop mode
Low Flow Cutoff set too high Configure Low Flow Cutoff to a lower setting or increase flow to a value
above the low flow cutoff
PZR Activated Open PZR switch at terminals 9 and 10 to deactivate the PZR
Flow is in reverse direction Enable Reverse Flow function
Shorted coil Coil check – perform flowtube Test A and B on Table 5-3 on page 5-6
Empty pipe Fill pipe
Electronics failure Replace the electronics boards – see Replacing the
Electronics Module on page 5-7
Output at 21.6 mA Transmitter not ranged properly Reset the transmitter range values – see Analog Output Zero(LRV) and
URV (Upper Range Value) on page 4-6;
Check tube size setting in transmitter and make sure it matches your
actual tube size – see Line Size on page 4-7.
Output at alarm level Electronics failure Cycle power by removing and installing the power fuse. If alarm is still
present, replace the electronics boards. See Replacing the
Electronics Module on page 5-7.
Pulse output at zero, regardless
of flow
Wiring error Check pulse output wiring at terminals 5 and 6. Refer to wiring diagram
for your flowtube and pulse output.
PZR activated Open PZR switch at terminals 9 and 10 to deactivate the PZR.
No power to transmitter Check pulse output wiring at terminals 5 and 6. Refer to wiring diagram
for your flowtube and pulse output.
Reverse flow Enable Reverse Flow function
Pulse width too wide Reset pulse width – see Pulse Width on page 4-10
Pulse width too narrow Reset pulse width – see Pulse Width on page 4-10
Electronics failure Replace the electronics boards – see Replacing the
Electronics Module on page 5-7.
Communication problems with
the HART Communicator
4–20 mA output configuration Check analog power jumper (internal/external). The HART
Communicator requires a 4–20 mA output to function.
Communication interface wiring
problems
Incorrect load resistance (250 V minimum);
Check appropriate wiring diagram
Low batteries in the HART
Communicator
Replace the batteries in the HART Communicator – see the
communicator manual for instructions.
Oldrevisionofsoftwareinthe
HART Communicator
Consult your local sales office about updating to the latest revision
of software.
Error Messages on LOIor HART
Communicator
Many possible causes depending
upon the message
See the Error Messages Table for the LOI or HART Communicator