Det-Tronics SW9200x Slickwatch IR Oil Detection System - Manual (Page 18)

SYMPTOM: RATIO voltage is negative or 4-20 mA output is below 4 mA.
POSSIBLE CAUSE: The ZERO adjustment potentiometer located on the front panel is not set properly.
CHECK: Setting of ZERO adjustment potentiometer on front panel.
REMEDIAL ACTION: Adjust ZERO potentiometer until RATIO is 1.0 ±0.5 VDC (See Output Zero OPERATION/
PERFORMANCE CHECK procedure).
POSSIBLE CAUSE: Instrument malfunction.
CHECK: NUMERATOR and DENOMINATOR voltage when a bare flashlight bulb or bare 60 watt light
bulb is held in front of the receiver window.
REMEDIAL ACTION: Replace printed circuit boards one at a time and repeat CHECK. Contact factory if fault
cannot be located.
SYMPTOM: RATIO voltage is steady and does not appear to be responding to oil within field-of-
view.
POSSIBLE CAUSE: Malfunction of signal processing circuitry.
CHECK: RATIO voltage when a small amount of oil is introduced within the instrument’s field of view.
The RATIO voltage should increase above +2.0 VDC.
REMEDIAL ACTION: Substitute spare boards and assemblies until defective part is located and RATIO responds
properly to oil. Defective part can be returned to factory for analysis and repair.
SYMPTOM: Oil Alarm does not activate when oil is present in instrument’s field-of-view, or Oil
Alarm activates too frequently.
POSSIBLE CAUSE: Improper Oil Alarm threshold setting.
CHECK: Voltage at OIL ALARM SETPOINT test jack (grey) relative to SIGNAL GROUND (green).
REMEDIAL ACTION: Adjust setpoint if required. See Oil Alarm Threshold Adjustment procedure.
POSSIBLE CAUSE: Malfunction of Oil Alarm circuitry.
CHECK: RATIO voltage relative to voltage on OIL ALARM SETPOINT jack. If RATIO voltage exceeds
alarm setpoint, and alarm does not activate, a malfunction of alarm circuitry exists.
REMEDIAL ACTION: Replace Rear Panel p.c. board and/or Oil Alarm relay on Connector/Relay p.c. board.
SYMPTOM: Signal strength of NUMERATOR and DENOMINATOR decreases when water becomes
calm.
POSSIBLE CAUSE: Transmitter and receiver not properly aligned.
REMEDIAL ACTION: Repeat Alignment procedure.
SYMPTOM: RATIO output is negative or very positive and does not respond to oil on the water.
POSSIBLE CAUSE: Transmitter and receiver not properly aligned.
CHECK: NUMERATOR voltage.
REMEDIAL ACTION: If NUMERATOR voltage is less than +0.25 VDC, repeat Alignment procedure.
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