961-20A0-010 Datasheet, PDF (28/36 Pages) Magnetrol International, Inc. – Ultrasonic Single and Dual Point Level Switches

3.7 Troubleshooting
Caution: In hazardous areas, do not remove the housing cover until
power is disconnected and the atmosphere is determined
to be safe.
The Model 961/962 has a unique diagnostics feature to
assist in troubleshooting should a failure occur. A micro-
processor in the electronics continuously monitors all self-
test data. Should a fault occur, the microprocessor can
determine whether the malfunction is due to the electron-
ics, transducer, piezoelectric crystals, or the presence of
environmental noise. A push button and Fault LED is
used to assist in troubleshooting the switch:
• One flash of the Fault LED indicates a problem with the
transducer, piezoelectric crystals, or the interconnection
wiring
• Two flashes of the Fault LED indicates a problem with one
of the electronics boards
• Three flashes of the Fault LED indicates presence of exces-
sive levels of environmental noise
If a fault condition is detected by a line-powered 961/962,
the MALF LED will turn off indicating that the MALF
relay has been de-energized, and the FAULT LED will
turn on. If a fault condition is detected by a loop-powered
961, the 8 and 16 mA LED turn off, and the FAULT
LED will turn on. If a fault condition is detected by a
loop-powered 962, all three LEDs will turn off.
The push button indicated below should be pressed and
held while observing the LED:
Electronics Version
961 with 5 amp relays
961 with current shift
962 with 5 amp relays
962 with current shift
Push Button
LEVEL TEST
LOOP TEST
LEVEL TEST
LOOP TEST
LED
FAULT
FAULT
FAULT
16 mA
If the above diagnostic LED flashes once when the push
button is pressed, the most common issue is the intercon-
nection wiring between the electronics and the transducer.
Check all wiring inside the housing to make sure that all
wires are secure in their respective terminal blocks. Make
sure that all the terminal block screws are fully tightened.
If all wires are secure then contact the factory. A replace-
ment transducer may be needed. See Section 3.9, Model
Number, for proper replacement part numbers.
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51-646 Echotel^® Model 961 & 962 Ultrasonic Level Switches