Polytec TMS-350 TopMap In.Line, Hardware Manual

Page: 32 / 59

4-2
4 Measuring
Measuring Data acquisition is fully controlled by the software. You can now make
measurements as described in your software manual.
4.2 Making High-precision Measurements
Assembly To rule out any external disruptions during the measurement, you should set
up the sensor head and the object on a vibration-isolated table.
INFORMATION
Do not place moving parts, e.g. the PC, on a vibration-isolated table because
the measurement results could be affected or falsified!
INFORMATION
To adjust the precise measurement distance, either the interferometer or the
measurement object needs to be fixed in a way that it can be moved!
Reference
measurement
A reference measurement which is balancing the curve in the field of view
made by Polytec is included in the TMS software on delivery. This reference
measurement is automatically subtracted from your measurement after every
measurement.
Compensate for
measurement
inaccuracy
If you exchange the reference filter (refer to S
ECTION
4.3), additional
measurement inaccuracies in the range of less than 1 μ m can occur. To
compensate this error, please proceed as follows:
1. Position a high-precision optical flat (e.g. a
λ / 20 plate, available as an
option) so that the optical flat is aligned approximately towards the beam
exit window and parallel to the connecting flange on the beam exit
window.
2. Now set the parallel plate to be at the right measurement distance. The
distance from the beam exit window must be approx. 40 mm (refer also to
F
IGURE
6.1).
You have to find the interferences to determine the correct measurement
distance. To do so, proceed as follows:
3. Start the TMS software.
After starting the software, the measurement window appears in the
application window and the reference mirror is positioned in the middle
of the range of travel.
4. You can see the live video image. If the image is too dark or too bright,
adjust the exposure time as described in your software manual.
5. To find the interferences, set the precise measurement distance. To do so,
slowly change the position of the interferometer or the optical flat until the
interferences are visible in the software.
A measurement range of ±0.24 mm is available.