Det-Tronics SW9200x Slickwatch IR Oil Detection System User Manual
Page 24
described began. The six extra seconds are the result
of six 1 second intervals of clean water that were
observed during the first 100 seconds of the measure-
ment cycle.
INSTRUMENT OUTPUT
If the OUTPUT SELECT switch on the front panel is set
on position V, the RATIO output at terminal 1 of the junc-
tion box will be the standard 0 - 10 VDC. If the O posi-
tion is used, the RATIO output at the junction box will be
0 VDC when the OIL Alarm relay contacts are closed
and approximately -14 VDC when the Oil Alarm relay
contacts are open.
INSTRUMENT SENSITIVITY
The instrument can be decreased in sensitivity to nui-
sance oil in the water or to residual sheens by increasing
either the OIL DURATION thumbwheel setting or the
%OIL thumbwheel setting, or both. Likewise, the instru-
ment can be increased in sensitivity to small spills by
decreasing either the OIL DURATION thumbwheel set-
ting or the %OIL thumbwheel setting, or both. The opti-
mum settings for the alarm conditions depend on the
user’s requirements and the condition of the water sur-
face at the installation site. The settings are best deter-
mined by trial and error until the nuisance alarm rate due
to residual or background oil is reduced to an accept-
able level.
The factory settings for the Selectable Criteria Alarm
board are 60 seconds and 50%. These settings can be
changed without removing the receiver assembly from
the housing. Open the receiver cover and locate the
Selectable Criteria Alarm board to the right of the filter-
wheel motor. The yellow thumbwheel switch at the top of
the board is %OIL (X10). The other three white thumb-
wheel switches are OIL DURATION (SECS). The top
switch is units, the second switch is tens and the bottom
switch is hundreds.
OIL ALARM RELAY CLOSURE
The Oil Alarm relay contacts are closed when clean
water is observed. When oil film is observed by the
instrument, the Oil Alarm relay contacts will open after a
delay of N seconds (N is the setting of the OIL DURA-
TION switches). The Oil Alarm relay contacts will remain
open for approximately 60 seconds and then will close,
even if oil is still present. If oil continues to be observed,
the Oil Alarm relay contacts will close again for approxi-
mately 60 seconds each 1000 seconds until the oil spill
is removed.
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95-8409
WAVE ANGLE (DEGREES)
θ
100
10
1
OPERATING HEIGHT (FEET)
A1608
1
10
100
Relationship of Wave Angle to Operating Height