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Once this occured the first time, measurement is considered as completed and
acoustic signal is issued.
4.2.2 Selectable Stability Modes
As samples are different, Novasina offers different stability modes and settings to
take the sample‘s properties into the account. The following modes and options
are available:
•
Slow: is equivalent to a stability time of 6 minutes.
•
Average: is equivalent to a stability time of 4 minutes.
•
Fast: is equivalent to a stability time of 2 minutes.
•
ISO 18787: Measurement according ISO 18787:2017 standard with requi-
rements in terms of temperature (25 +/-1°C) and determination of the final
measurement point by reaching a plateau defined with a maximum amplitu-
de of 0,0003aw, by three consecutive measurements and by stability over 1
min. By monitoring both stability criteria of the ISO standard, a wrong mea-
surement by an initial over-or undershoot of the value due to temperature
difference of chamber and sample can be avoided.
•
Manual: a new submenu is available in chamber settings where you can
enter the requested stability time in minutes.
•
Quick: at-line mode for production, every measurement is finished within
max. 10 minutes as long as temperature is set in the range of 20°C to 30°C
•
Query: a query about the requested stability time is issued, every time a
measurement is started.
Note:
A stability time below 2 minutes is not recommended for batch release
measurements in final QC as equilibrium could not be established in a way to
ensure the stated specs.
4.2.3 Which mode for which products?
It is a difficult question and there is no generic answer. Your local Novasina agent
can assist you in finding the best mode or stability time for your product. As a
rule of thumb one can say, the drier the product, the shorter the stability time
(or going towards F mode). The more long chain sugars are involved, go to A
mode or stability observation time of 3-4 mins. Once fat/oil is involved, S mode
or stability observation time higher than 5 mins are necessary.
It is also possible to find out yourself. Select „Manual“ as stability mode and then
enter a stability observation time according to the rule o thumb above. Once
measurement is finished, let the sample in the chamber for another 20-30 mins.
If the actual value differs more than +/-0.005aw from the green displayed stable
value, add another 2 mins to stability observation time and redo the measure-