INVUE CR288 CONCENTRATION MONITOR
23
Installation and Use Manual | Entegris, Inc.
CLEANING THE SENSOR WINDOW
Over time, some fluids may develop a film that coats
the sensor’s optical window. This may cause poor
sensor performance. If the Re-zero procedure does
not correct the issue, the sensor may be disassembled
to clean the optical window.
1. Disconnect the sensor cable and remove the
sensor from the system.
NOTE: Do not twist the cable to remove.
2. Remove the hole plugs, socket head cap screws,
and washers. Separate the sensor from the body.
Remove the gasket from the body.
3. Carefully clean the optical window with an
appropriate solvent and a clean cloth.
4. Rinse off with DI water and dry with a lint-free
wipe.
5. Place the mounting plate against the bottom of
the body.
6. Install the gasket back into the top of the body.
Carefully center the window into the gasket.
7. Assemble the sensor to the body and insert the
washers and socket head cap screws.
8. Torque the socket head cap screws to 0.14 to
0.17 N•m (20 to 25 in•ozf) using a cross pattern.
9. Torque the cap screws again, to 0.31 to 0.34 N•m
(45 to 48 in•ozf), using a cross pattern. Insert the
hole plugs.
10. Re-initialize the sensor
a. Make sure the sensor is clean, dry and placed in
lighting similar to system conditions
b. Go to the Chemical Calibration tab and select
Factory Calibration tab
c. Press the Initialize Sensor button (the software
will take about 10 seconds to complete)
d.
IMPORTANT
– If the initialization is successful,
go back to the Sensor Calibration Tab and “Save
Memory”
11. Reinstall the sensor into the system and recon-
nect the sensor cable.
12. Pressurize the system and inspect for leaks.
13. Follow the Re-zero procedure.
Figure 34. Underview of sensor.
TROUBLESHOOTING
Possible reasons for measurement inaccuracies
include, but are not limited to:
• Window fouling
• Restricted flow across the sensing surface
• Bubbles or air pockets
• Inadequate light shielding
• Environmental noise
• Delamination of the sensing surface (rare)
Examining the TIR curve on the Diagnostics Tab is a
useful step in identifying the source of measurement
inaccuracies. See
Diagnostics Tab
.
Figure 35. Healthy TIR curve.
Optical window
