User guide

Rev. 12/97 -37- D77X
PART 4 - TROUBLE SHOOTING
CONDITION POSSIBLE CAUSE
Unit does not turn “ON” when power is
applied
? Verify that AC power source is live.
? Test the fuse
FAULT CONDITION is indicated on LCD
indicator
? Ensure that the transducer is properly
mounted to the pipe.
? Verify that transducer connections are
correct
? Ensure that the pipe is full of moving
liquid.
? If SIGNAL STR is less than 100 counts
and flow rate is greater than 1 FPS [0.3
MPS], adjust GAIN control (R13 on the
Main PCB) till SIGNAL STR reaches at
least 130 counts.
? On cleaner liquids, move the
transducers closer to a 90
o
pipe elbow.
? If GND connection and pipe are at
different potentials, ground D77 to pipe
potential.
? If Variable Frequency Drives are being
utilized, verify that the D77 obtains a
flow indication when the pump turns
OFF. If it does, contact the Dynasonics
factory.