To start the verification process, select 1 VERIFICATION in the Main menu of your sensor. The first verification display instructs you on the pre-verification procedure:
When you are finished with the preparations, press CONTINUE (right-most soft key) to start the verification process.
The verification itself is done by the refractometer system. Follow the instructions on screen and apply one RI liquid at a time on the sensor and press VERIFY (right-most soft key). See the following figure.
| Clean and dry the prism and the sample holder very carefully between the RI liquids. Use a suitable solvent, for example ethanol or IPA (Isopropyl alcohol). |
To check that the standard liquid is properly wetting the prism, it is possible to 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 ten times and uses the average of these measurements. Measuring each verification liquid takes approximately 10 s, during which the measurement progress display is shown, as shown in the following figure. 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 finishes the verification procedure and calls up the verification results.
If verification is successful, meaning that all measurements are within ±0.0004 of the nominal values, you get the message VERIFICATION OK, see the following figure.
| The sensor verification concerns only the refractive index nD measurement. The calculation of concentration from nD and process temperature TEMP is not included, see Calibrating concentration measurement. |
If the verification fails, see Corrective action.