K-Patents PR-23 Troubleshooting Guide - Manual (Page 6)

TROUBLESHOOTING GUIDE
FOR PR-23 ALL MODELS 6 (14)
January 9, 2015
K-PATENTS OY

Postal Address: P.O.Box 77, FI-01511 Vantaa, Finland

Street Address: Elannontie 5, FI-01510 Vantaa, Finland

Tel. int.+358 207 291 570
Fax int.+358 207 291 577  [email protected]  www.kpatents.com  Vat No. FI03035575  Business ID 0303557-5  Registered in Helsinki
Any outside light can also affect the shape of the optical image, therefore, the prism should be covered when
inspecting the optical image. If the optical image is not as shown above, the prism should be cleaned with a
glassfiber brush, and inspected for scratches or marks.
Figure 6
Optical image and slope during measurement
During operation the optical image bends at a certain position which depends on the R.I. of the measured
medium. Also a clear dip appears on the slope image. A greater dip on the slope image demonstrates better
optical image quality and more stable measurement.
The QF-value is related to the quality of the optical image and the slope (higher QF is better). However, the
sharpness of the slope and the QF-value can vary significantly depending on the application. The best way
to exploit the QF-values is to follow and record the changes in the QF which can reveal the changes on the
prism surface.
If the prism is damaged, there can be several dips on the slope which can disturb the measurement. As long
as the slope of the real measurement point is steep, the measurement is not lost. In case of prism coating
the slope typically weakens which can lead to losing of the measurement. However, low optical image, high
spikes, irregular form of the optical image or very weak slopes indicate that actions are required. Typically,
visual check of the prism condition and cleaning it with a glass fiber brush is enough to resolve measurement
related problems. Replacement of the prism should be considered if there are any marks on the prism
surface. Implementation of wash system or wash optimization should be considered, if prism coating causes
frequent problems.