Each Vaisala K-PATENTS® refractometer is provided with a calibration certificate comparing a set of standard liquids to the actual refractometer output. Therefore, the calibration and accuracy can be easily verified on-site with the certified refractive index liquids and menu guided verification procedure.
For verification you need:
- Universal sample holder PR-1012 (see the following figure). The sample holder keeps the sample on the prism surface and also keeps the ambient light out.
- A set of standard refractive index liquids.
- Cleaning solution (ethanol) to clean the refractometer prism and the sample holder.
The verification of the PR-43 refractometer calibration is made using a set of standard refractive index liquids with the nominal values at +25 °C (+77 °F):
The accuracy of the certified standard refractive index liquids is ± 0.0002 and they can be traced back to national standards: NIST Standards # 1823 and # 1823II. As the specified accuracy of PR-43 is ± 0.0002, then the representative level is the sum of the 2 accuracy specifications, that is, ± 0.0004.
Vaisala provides a set of standard R.I. liquids, PR-2300, containing these 5 liquids. The set can be ordered directly from Vaisala or through your representative.
You can perform a verification by connecting to the refractometer with Ethernet or by using a Multichannel user interface MI or Compact user interface CI.
In the web interface, go toand follow the instructions on the page.
In MI, tap the 54 PR-43-AC/AP instruction manual 3 dots in the app for the refractometer to be verified, then choose Verification. Tap the question mark in the Verification display to get verification instructions.
In CI, go toand follow the instructions on screen.
|For a successful verification, the refractometer and the standard refractive index liquids must be at room temperature, +25 ± 5 °C (+77 ± 9 °F).|
To check that the standard liquid is properly wetting the prism, monitor the optical image during the verification procedure. The optical image should show a sharp shadow edge.
The instrument measures each verification data point 10 times and uses the average of these measurements. Measuring each verification liquid takes a few seconds, during which the measurement progress display is shown. Please wait until the verification step 2 display reappears before proceeding to next verification liquid. The limit for acceptance is that all measurements must be within ± 0.0004 of the nominal values.
If message VERIFICATION FAILED is shown, do the following:
- Check that the prism and the sample holder are absolutely clean and the sample holder sits tightly on the refractometer tip before a standard liquid is applied.
- Make sure the standard liquids are in good condition and not past their expiration date.
- Inspect the prism surface, checking that it is flat and glossy without any scratches.
Repeat the verification procedure. If the verification still fails, fill in the PR-43 refractometer verification form, found at the end of this manual. The refractometer serial number is shown in the upper right corner of each display. The list of CCD and TEMP values are found on the Verification results display. Send the form to your Vaisala K-PATENTS® representative or email the collected data to firstname.lastname@example.org and wait for further instructions.