FMG490 INSTRUCTIONS
Page 22
TROUBLESHOOTING & ERROR MESSAGES
Troubleshooting
Problem
Probable Causes
Things to try…
Blank Display
Faulty wiring from power source to
meter
Check for incorrect wiring. Measure voltage with
DMM where red and black wires connect to
terminal block TB1 on back side of display. Verify
correct polarity and confirm that voltage is steady
and between 9Vdc and 32Vdc
Backup battery has not been plugged in Plug in the battery
Dead backup battery
Replace battery
Flow rate reading fluctuates
excessively when flow is
unchanging
Excessively turbulent or unsteady flow
due to partially closed valves or other
flow obstructions
Eliminate or minimize causes of flow disturbances
or increase meter damping
Pipe not full
Provide back pressure or other means to ensure
pipe is filled
Pulsing flow due to combining multiple
upstream flow sources
Move connection point further upstream
Insufficient mixing of upstream
chemicals
Move chemical injection downstream from meter
Low fluid conductivity < 20 µS/cm
Replace with different type of meter
Noisy electrical environment
Improve grounding at meter and nearby potentially
noisy electrical equipment. Increase distance
between meter and electrical noise sources.
Defective or noisy AC switching power
supply
Replace power supply
Flow Rate appears correct but
pulse/ frequency output is low,
erratic or absent
Wiring incorrect
Compare wiring with appropriate wiring
recommendations
External device input impedance too low Use sourcing rather than sinking interface
connection
Cable too long
Reduce interface pull-up resistance
Flow Rate appears correct
but pulse/frequency output is
erratic and/or too high
Electrical noise sources interfering with
pulse frequency signal
Isolate, remove or reduce noise sources. Move
meter control cable away from noise sources.
Increase pulse damp setting (PDAMP)
Wrong type of cable
Use only twisted pair cable and ensure both signal
wires are on same twisted pair
Grounding problem
Improve or try different grounding method
Troubleshooting
Error Messages
Under certain conditions an error message may be displayed.
Message
Description
Notes
INIT
Initialization is occurring during power up.
EMPTY PIPE
Fluid is not detected between the sensing electrodes.
Loop output = 22.8mA
LO in battery icon
Battery is getting low, replace soon. Meter still functions.
Above 6.4V, OK appears in icon
BATT END
Battery is very low (approx. 6.1V). Totalizer stops updating.
Loop output = 4mA
LOW VOLT
Incoming external power is very low and backup battery is dead
or not connected
Loop output = 4mA
COIL FAIL
Coil current too high or too low (short or open).
Loop output = 22.8mA
COMM FAIL
Communication between transmitter and sensor board fails.
Loop output = 22.8mA
OVER RANGE
Rate exceeds number of digits that can be displayed. Adjust units.
Loop output = 4mA
