Det-Tronics SW9200x Slickwatch IR Oil Detection System - Manual (Page 13)

INFRARED PHOTODETECTOR
TEMPERATURE ADJUSTMENT
The infrared photodetector is thermo-electrically (TE)
cooled to increase its sensitivity to infrared light and to
maintain a constant sensitivity over a wide range of
ambient air temperatures. Two temperature settings are
available on the AGC/TE Cooler p.c. board. The JP-1
setting (two left pins) maintains the detector temperature
at approximately -20o C and the JP-2 setting (two right
pins) maintains a temperature of approximately 0o C.
The coolest temperature setting (JP-1) should be used
under normal ambient conditions and for normal and
long operating heights. The JP-2 setting should be used
for short operating heights and in extremely hot environ-
ments where the cooler may not be able to maintain a
constant -20o C temperature.
Section 3
Maintenance
GENERAL PRECAUTIONS
As with all precision electro-optical equipment, care
must be taken to avoid sharp blows to the instrument.
Do not drop it or allow heavy objects to strike it. Do not
touch the windows, lenses, lamps, filters, or other optical
surfaces with bare hands. Customary precautions for the
use of explosion-proof instruments in hazardous environ-
ments should be observed. In procedures where either
cover, window assembly, or junction box are to be
opened when circuits are alive, first ensure that no haz-
ardous vapor conditions exist.
WARNING
Live line voltage is exposed at several points within
the SW9200. This is potentially dangerous, and
contact by maintenance personnel must be avoid-
ed.
ACCESS TO INTERNAL COMPONENTS
All internal components of the transmitter and receiver
are mounted to the cover (see Figure 3). Access to
these components is obtained either by swinging open
the cover on its hinges, or by removing the cover and
associated components from the housing.
1. Disconnect all power to the instrument. Rotate the
mounting plate 180 degrees so that the instrument
faces up.
2. Remove the 20 bolts which hold the cover to the
housing.
3. Swing open the cover to permit access to the con-
nector(s). DO NOT OPEN the receiver cover more
than three inches, to prevent undue stress on the
connector(s).
4. Disconnect the connector plug(s) from the recepta-
cle(s). The transmitter has one connector and the
receiver has two connectors. The instrument can be
inspected or serviced on-site while the cover is
opened and attached by its hinges. If service is to
be performed off-site, the cover and attached com-
ponents may be removed from the housing as
described in Step 5.
5. With the cover swung open, lift the cover up to dis-
engage the hinges. Care must be taken to avoid
scratching the flanges or damaging the internal
components.
Each time the instrument housing is opened for mainte-
nance, the desiccant pack should be checked. When
the desiccant is expanded only slightly, no change is
necessary. If it is expanded to twice or more its original
size, the desiccant should be replaced. Extra desiccant
packets are available from Detector Electronics (see
Recommended Spare Parts List). DO NOT replace the
desiccant until all other maintenance procedures have
been completed. Remove the old desiccant by cutting
the strings that attach it to the power supply wiring.
Remove the plastic bag on the replacement packet and
tie it to the power supply wiring. Be sure that the desic-
cant packet is securely attached to the power supply
wiring so that it cannot come loose inside the housing.
Close the cover immediately after replacing the desic-
cant.
To reattach the cover to the instrument housing:
1. Holding the cover completely open, slide the cover
hinge pins onto the housing hinges. Do not tighten
the hinge screws.
2. If necessary, replace the desiccant pack.
3. Reconnect the plug(s) and receptacle(s) in the
housing and close the cover. Guide the cable to
insure that it is not pinched.
4. Rotate the mounting plate 180 degrees so that the
instrument is in position for operation.
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