Stability System - Novasina LabTouch-aw Operating Instructions Manual

Stability System

6.2
18
If the instrument is switched-off and hot sample is placed into the chamber,
the sensor might be destroyed, especially if additional vibrations are present.
Please do not place any sample into the measurement chamber while the
instrument is switched-off!
Note:
The condensation alarm does not work properly if the infrared temperature
sensor is blocked by an inserted, chemical sensor protection filter.
6.1.2 Start a Measurement
Program the respective stability parameters, depending on the sample proper-
ties (see chapter 6.2).
Start a measurement as follows:
• Switch to the main menu screen
• Press the "Start" button.
-> The measurement is started and the measurement screen is displayed
End of measurement :
If stability is reached, the instrument takes the reading which is as well the end
of the measurement. A "beep" indicates it acoustically.
Note:
• If the stability times are set in an inappropriate way, the readings might be
taken too early (stability not completely accomplished) or measurement
time is extended unnecessarily.
• Always remove the sample before shutting-down the instrument. The dew
protection is not active once the instrument is switched off and the sensor
might be damaged in this case. In addition, volatile substances in low
concentration can accumulate and deteriorate the sensor's performance.
To it, the warm-up phase is remarkably longer if a sample with high water
activity is not removed after finishing the measurement.
The key to a successful and reliable water activity measurement is the fact
that the reading has to be taken once the equilibrium between the free water
in the sample and the surrounding air has been established. Even as different,
more or less successful approaches are present in the market, Novasina has
its own, unique equilibrium detecting system which is the most accurate and
reliable one, proven by hundreds of satisfied customers.
Theoretically, a full established equilibrium is reached after endless time period.
Of course, there must be a tradeoff as the measurement results have to be
available within reasonable time. For that reason, the LabTouch-aw is equipped
with a so called stability indicator, which supports the user in finding the best
compromise between measurement duration and sufficient accuracy.