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No. 99MBC071A
7.2 Measuring Unit
This section describes the method of maintenance and inspection of the Measuring Unit.
7.2.1 Laser emission status indicator LED
This LED turns on to indicate that laser emission is on. This is done to highlight safe
operation.
Laser emission
indicator LED
7.2.2 Cleaning optical parts
Periodically clean the protection glass of the emission window and reception window. If the
protection glass is contaminated, not only is the measuring accuracy reduced but the display
unit mistakes the dimension of dust or foreign matter with that of the measuring object.
• Checking with an oscilloscope
On the rear panel of the Display Unit, there is a SCAN SIG.-1 connector provided for
monitoring photo-electrical signals.
Set up the oscilloscope as follows:
• Vertical sensitivity: 0.1V/DIV (if used with a 1/10 probe)
• Horizontal sensitivity: 100 µS/DIV
(a) Normal
Approx. 620µs
Approx. 4 V
(b) Soiled glass (c) Soiled glass
Clean the protective glass according to the following procedure, if the oscilloscope waveform
(b) or (c) was observed.
For cleaning, use either a blower or wipe lightly with gauze dampened with a small amount
of ethyl alcohol.
IMPORTANT Clean windows are vital for precision measurement in the LSM system. Handle the
glass with care.
