How To Perform Measurements; First Measurement - Novasina LabTouch-aw Operating Instructions Manual

6.

How to Perform Measurements

First Measurement

6.1
temperature in the measurement screen turns red in this case and the user
will be noticed in the status bar by a respective hint.
• If the environmental temperature is changing during an on-going measurement
in a way that the programmed temperature can not be reached, the displayed
temperature turns red as well and the instrument will not reach stability,
means the measurement can not be finished.
The notice "retarded (temp)" appears below the stable indicator.
• Stability is foreclosed if nominal temperature cannot be reached plus if
"Stability check temperature" is activated . Retarded (temp) is displayed
in this case as well.
Note:
The programmed temperature must be between 15°C and 30°C!
Information about starting a measurement can be found in this chapter.
Prepare the sample by cutting it into small pieces and fill the sample cup till the
visible first rim. This is approximately 2/3 of the sample cup. As the water activity
is a relative measurement, the amount of sample is negligible, means, it does
not matter how much sample is placed in the sample cup, the result will be the
same. Just note that the bottom of the sample cup should be covered at least
to achieve reasonable performance. Do not overfill the sample cup, otherwise
some sample will be pressed into the white sensor protection filter which can
cause wrong measurements, thereby requires immediate filter replacement.
6.1.1 Insert a Sample
Place the prepared sample cup into the metal indentation of measurement
chamber and close it.
• If the sample is too hot (more than 4°C above environmental temperature),
an alarm is issued and the chamber has to be opened as soon as possible
to avoid condensation within the same. At the same time, a respective
symbol is displayed.
Condensation has to be avoided as water droplets are formed in the mea-
surement chamber and wrong measurement results for the current and the
following samples will be the consequence. The sensor itself is actively and
reliably protected by a dew protection as long as the instrument is switched on.
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