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No. 99MBC032A
7.2 Measuring Unit
This section describes the method of maintenance and inspection of the Measuring Unit.
7.2.1 Cleaning optical parts
Periodically clean the protection glass of the emission window and reception window. If these
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.
7.2.1.1 Checking method of the reception signal using an oscilloscope
There is the “SCAN SIG”, the test terminal for the reception signal, on the rear panel of the
main unit. Check the “SCAN SIG” test terminal with an oscilloscope probe.
The setting of an oscilloscope is as shown below.
• Vertical sensitivity: 0.1V/DIV (when using a 10-times probe(x10) )
• Horizontal sensitivity: 50 µs/DIV
Approx. 310 μs
Approx. 4 V
(a) normal waveform
(b) waveform when the protection glass is contaminated
Clean the protection glass according to the following procedure, if the oscilloscope
waveform(b) 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.
7.2.2 Replacement of protection glass
For temporarily removing the protection glass for replacement or cleaning since it is damaged
or contaminated, use the following procedure.
Unscrew the 4 to 6 screws
that secure the protection glass.
Follow the above procedure in reverse.
If the protective glass is removed, dust may enter
inside of the unit. If the ambient air contains moisture,
the glass may dim. Perform disassembly/reassembly
in a room which is free from dust and well-ventilated.
Disassembly procedure
Reassembly procedure
Precautions
