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Reference Manual
00809-0100-4444, Rev AC
Section 9: Troubleshooting
January 2015
Troubleshooting
Reading does not appear to
be within rated accuracy
• Transmitter, control system, or
other receiving device not
configured properly
• Check all configuration variables for the transmitter, sensor,
communicator, and/or control system
• Check these other transmitter settings:
•Sensor calibration number
•Units
•Line size
•Perform a loop test to check the integrity of the circuit
• Electrode Coating •Enable Coated Electrode Detection diagnostic
• Use bullet-nose electrodes
• Downsize sensor to increase flow rate above 3 ft/s
• Periodically clean sensor
• Gas/air in line • Move the sensor to another location in the process line to ensure it is
full under all conditions
• Moisture problem •Perform the sensor tests - see Table 9-8 on page 168
• Insufficient
upstream/downstream pipe
diameter
• Move sensor to a new location with 5 pipe diameters upstream and 2
pipe diameters downstream if possible
• Cables for multiple magmeters
run through same conduit
• Use dedicated conduit run for each sensor and transmitter
• Improper wiring • If electrode shield and electrode signal wires are switched, flow
indication will be about half of what is expected. Check wiring
diagrams.
• Flow rate is below 1 ft/s
(specification issue)
• See accuracy specification for specific transmitter and sensor
• Auto zero was not performed
when the coil drive frequency
was changed from 5 Hz to 37 Hz
• Set the coil drive frequency to 37 Hz, verify the sensor is full, verify
there is no flow, and perform the auto zero function
• Sensor failure–shorted
electrode
• Perform the sensor tests - see Table 9-8 on page 168
• Sensor failure–shorted or open
coil
• Perform the sensor tests - see Table 9-8 on page 168
• Transmitter failure • Verify transmitter operation with an 8714 Calibration Standard or
replace the electronics board
Noisy Process
• Chemical additives upstream of
magnetic flowmeter
• See Troubleshooting high process noise on page 158
• Move injection point downstream of magnetic flowmeter, or move
magnetic flowmeter
• Sludge flows–mining/coal/
sand/slurries (other slurries with
hard particles)
• Decrease flow rate below 10 ft/s
• Styrofoam or other insulating
particles in process
• See Troubleshooting high process noise on page 158
• Consult factory
• Electrode coating • Enable Coated Electrode Detection diagnostic
• Use a smaller sensor to increase flow rate above 3 ft/s
• Periodically clean sensor
• Gas/air in line • Move the sensor to another location in the process line to ensure it is
full under all conditions
• Low conductivity fluids (below
10 microsiemens/cm)
• Trim electrode and coil wires – see Cable preparation on page 29
• Keep flow rate below 3 FPS
• Integral mount transmitter
• Use component cable - see Table 2-11 on page 27
Table 9-7. Common Magmeter Issue (continued)
Symptom Potential cause Corrective action