Appendix – Det-Tronics SW9200x Slickwatch IR Oil Detection System User Manual

Page 22

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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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