visilab AK50, Technical Notes

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TECHNICAL NOTES FOR USERS - NOTE #033
The Procedure for Calibration For Infrared Moisture Meters
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true moisture and you can compare the two readings. You can then keep the sample under the meter and do the
adjustment to fine tune to force the meter reading exactly the same. The fine tuning (Adjust) is in AK30/40 in
option "9=More.." and "4=Adjust". Type in some small decimal number to see what happens. Iterate to get
the correct reading. Before leaving the menus, save the table and possibly also the new configuration the main menu,
if necessary.
Do not forget to download the library to your PC to save your valuable work to a safe folder. Always modify the library name too.
If you will need to use the dry weight instead of the default total weight moisture, you would need to do the conversion for each
moisture reading according to:
total-% * 100 total-% * 100
total-% * 100 total-% * 100
total-% * 100
dry-% = -------------------- dry-% = --------------------
dry-% = -------------------- dry-% = --------------------
dry-% = --------------------
(100 - total-%) (100 - total-%)
(100 - total-%) (100 - total-%)
(100 - total-%)
Tips and Tricks Tips and Tricks
Tips and Tricks Tips and Tricks Tips and Tricks
With thin papers (BW < 150 g/m2) the paper is usually behaving with one-sided infrared moisture meters so that the total moisture
can be measured and sidedness is not so important. For best results, measure both sides of the sample. However, if you have climatized
the sample properly, this does not give any extra information. This is sheet calibration and it is performed for highest accuracy over
a black aluminum plate, one sheet at a time. Never keep other papers under the sample with thin papers while measuring.
If the sides are different, on the other hand, like one side coated and the other not, then it is advised to keep the side information
apart from each other. They really behave slightly differently. One has to decide which side is important for practical measurements
and perform the calibration for that side alone.
With thin papers sometimes one would need instead of sheet calibration also the reel calibration. This has an infinite BW and it can
be simulated at calibration time easily. While measuring in the chamber, always keep a bunch of similar or identical papers as the
background over which the actual sample is placed. Keep the resulting bunch rather tight when doing measurements to avoid any
air gaps between them. The signal readings will now be those corresponding to reel measurements. In this way, you might be able
to generate two calibrations with the same effort, in simple steps: one for sheet (black background) and another for reel (stack
background).
With thick papers it does not matter if you have any other papers under the sample or not. If it does, then you should have both
sheet and reel calibrations.
While waiting the samples to climatize for hours, set the meter to LowPower mode to avoid generating extra heat to the chamber.
That would unnecessarily load the control system and possibly slow down the whole process.