To start the verification process, select Main > VERIFICATION.
The first verification display
instructs you on the pre-verification procedure:
When you are finished with the preparations, press CONTINUE (rightmost soft key) to start the verification process.
The verification itself is done by the refractometer system. Follow the instructions on
screen and apply one R.I. liquid at a time on the sensor and press VERIFY (rightmost soft key).
Clean and dry the prism and
the sample holder very carefully between the R.I. liquids. Use a suitable solvent, for
example ethanol or IPA (isopropyl alcohol).
To check that the standard liquid is properly wetting the prism, press soft key
OPT. IMAGE.
The optical image should show a sharp shadow edge, see the following figure.
A verification data collection method is implemented in the DTR. The instrument
measures each verification data point 10 times and uses the average of these measurements.
Measuring each verification liquid takes approximately 10 s, during which the measurement
progress display is shown. Wait until the VERIFICATION STEP 2 display reappears before proceeding to the next verification liquid.
The sample holder keeps the sample on the
prism surface and also blocks the ambient light from reaching the prism.
Press COMPLETE in the verification display to finish the verification procedure and to call up the
verification results.
If verification is successful, meaning that
all measurements are within ±0.0004 of the nominal values, message VERIFICATION OK is shown.
The sensor verification
concerns only the refractive index nD measurement. The calculation of
concentration from nD and process temperature TEMP is not included. For more
information, see Calibrating concentration measurement.