A 4 Cleaning Optical Components; A 4.1 Contamination - MICRO-EPSILON confocalDT IFD2410 Series Operating Instructions Manual

Appendix | Cleaning Optical Components
A 4 Cleaning Optical Components
A 4.1 Contamination
Contamination of optical surfaces and components can increase the dark value and affect sensitivity and accuracy. To
prevent this, it is necessary to clean the optical components and record the dark value. "Dark value" refers to the inter-
fering reflections at boundary surfaces along the optical signal path. At each boundary surface or material transition,
the light waves are reflected to a certain extent at the transition and travel back in the fiber optics. The interfering signal
overlaps with the useful signal and forms a kind of signal noise.
If the interference signal is sufficiently high and the useful signal is relatively weak, the useful signal can no longer be
clearly identified. This may cause the controller to confuse a dark value peak with the measurement signal. Thus the
calculated distance of the measuring object does not match the actual one.
Sensor
Protective glass
Fig. 126 Optical boundary surfaces of a confocal measuring system
Conduct a dark correction, see
25.000
0
0 25
Video signal before dark correction (high dark value, blue line)
If the video signal corresponds to the condition before the dark correction, you must clean the optical boundary surfaces
within the measuring system. Clean the optical surfaces one by one to find the dirty component. You can observe how
cleaning improves the result by watching the dark signal of the video signal.
Continue with the section
i
Check and clean the protective glass of the sensor at regular intervals depending on the operating conditions.
Clean the system starting from the controller to the sensor. Always clean both components of a matched pair, i.e.
plug and socket.
confocalDT 2410/2411/2415
Sensor Cable
FC connector
Chap. 5.10.
50 75
Range [%]
Protective Glass of Sensor
Controller
E2000 connector
25.000
0
Video signal after dark correction
.
0 25 50
Range [%]
75
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