Det-Tronics SW9200x Slickwatch IR Oil Detection System - Manual (Page 22)

ORDERING INFORMATION
RECOMMENDED SPARE PARTS
Description Part Number
Transmitter lamp (250 watt) 102709-001
Filterwheel motor - 115 VAC 006624-001
1 Amp Fuse 107407-002
Alarm Relay, 115 VAC 102590-001
Alarm Relay, 230 VAC 102589-001
Desiccant Pack 102669-001
2 Inch Diameter Lens 005616-001
Test Power Cable 005791-001
Sync Demod p.c. board 005795-001
AGC/TE Cooler p.c. board 005797-001
Detector/Preamp assembly 005798-001
Rear Panel - standard or 4 to 20 mA 005794-004
Rear Panel - Film Thickness 005794-005
Rear Panel - Selectable Criteria 005794-006
Film Thickness Discriminator 005828-001
Selectable Criteria Alarm 005829-001
Single 4 to 20 mA Output 005793-001
For assistance in ordering a system to meet the needs of
a specific application, please contact:
Detector Electronics Corporation
6901 West 110th Street
Minneapolis, Minnesota 55438 USA
Telephone (612) 941-5665 or (800) 765-FIRE
Telex 6879043 DETEL UW
Cable Detronics
Facsimile (612) 829-8750
APPENDIX
This APPENDIX contains:
Film Thickness Discriminator Option
Selectable Criteria Alarm Option
Maximum Operating Height Graph
Voltage to Current Transfer Curve
Receiver Interconnections....................C2322-R130XC
FILM THICKNESS DISCRIMINATOR
OPTION
GENERAL DESCRIPTION
The oil slick detector bounces a beam of light off an
oil/water surface below and analyzes the reflected opti-
cal signal. The optical signal reflected from a thin oil film
(average thickness of less than 10 micrometers) pro-
duces a RATIO output between +1.0 and 10.0 VDC with
wide fluctuations due to irregularities in the film. The sig-
nal reflected from a thick oil film (average thickness
greater than 10 micrometers) produces a steady RATIO
output between +4.0 and +7.0 VDC. The optional Film
Thickness Discriminator printed circuit board processes
the differences between the reflected signals and pro-
vides information on whether a thin or thick oil film has
been detected.
FUNCTIONAL DESCRIPTION
In the first stage of processing, the RATIO signal into the
Film Thickness Discriminator is simultaneously com-
pared with a “window” and differentiated (the rate of
change is measured).
“Window” Condition
The RATIO signal is compared with a “window”, where
the upper limit is set by the potentiometer labeled “upper
window” and the lower limit is set by the potentiometer
labeled “lower window” on the printed circuit board.
When the RATIO output is within the “window” limits, the
voltage at the green test point is positive. When the
RATIO output is either above or below the “window”, the
voltage at the green test point is negative. The “window”
voltages are adjustable and are usually factory set at
+4.0 VDC for the lower window and +7.0 VDC for the
upper window.
Rate of Change Condition
The RATIO signal is fed into a differentiator, which sens-
es the rate of change of the signal. When the RATIO out-
put is steady and unchanging, the yellow test point is
positive. When the RATIO output is either increasing or
decreasing, the yellow test point is negative.
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