Troubleshooting/Service
322 UDC3500 Universal Digital Controller Product Manual 3/07
Step What to do How to do it
7
Check the Relays. Turn off power to the motor and to the
instrument. Disconnect and tag the field wiring
to the relays. Relay 1 (MOTOR – OPEN) is on
terminals 8 and 9. Relay 2 (MOTOR –
CLOSE) is on terminals 7 and 8.
Turn on power to the instrument. Put the
controller into Manual mode. Connect your
multimeter to terminals 8 and 9 and set the
multimeter to measure resistance. Now, vary
the output above and below the present value
and observe the “OUT” indicators and your
multimeter. When the “OUT 1” indicator is on,
then Relay 1 should be closed and there
should be only a few ohms between terminals
8 and 9. When the “OUT 1” indicator is off,
then Relay 1 should be open and there should
be infinite resistance between terminals
8 and 9. Listen for a click from the relay when
the OUT1 indicator changes state.
Repeat this test for Relay 2 by connecting your
multimeter to terminals 7 and 8. When the
“OUT 2” indicator is on, the relay should be
closed and there should be only a few ohms
between terminals 7 and 8. When the “OUT 2”
indicator is off, the relay should be open and
there should be infinite resistance between
terminals 7 and 8. Listen for a click from the
relay when the “OUT 2” indicator changes
state.
Relays measure correctly: Check motor. Refer
to manufacturer’s instructions.
Relays do not measure correctly: Go to Step
8.
8
Replace the Dual Relay Board. Installation instructions supplied with the new
board.
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