ROTRONIC HygroLab - Manual (Page 45)

IN-E-HyLab-V4_11
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
Instruction Manual
Document Type
HygroLab bench top indicator version 4:
instruction manual
Document title
Page 45 of 51
© 2006; Rotronic AG IN-E-HyLab-V4_11
c) Avoid warming up the probe, the sample holder or the product sample by touching or holding for
too long in your hand.
d) When using either the AW-DIO or the AwVC-DIO probe, check that the probe is on (this is the
default when powering up the HygroLab). When the probe is on, the red LED on the top of the
probe should be flashing The probe does not operate and the HygroLab does not get any signal
when the LED is not flashing. If necessary, press once on the red button located on top of the
probe.
17.5 Using the AwE mode (HygroLab 3)
Note: be sure to configure the instrument to display humidity as Aw and temperature in °C.
In the AwE mode, the HygroLab 3 constantly monitors the humidity and temperature signals from
the water activity probe. The HygroLab waits until the product sample has reached full equilibrium
and automatically ends the measurement at that time.
The HygroLab 3 performs the following tasks:
1) the stability of the humidity signal is constantly evaluated
2) the stability of the temperature signal is constantly evaluated
3) the measurement is automatically ended as soon as both humidity and temperature reach
equilibrium. At that time, the HygroLab makes a short beep and freezes the display.
The RS 232 output keeps being updated.
The criteria used to determine that a product sample has reached equilibrium can be modified by
the user (see Using the Standard Aw Mode).
The natural (or static) equilibration of most products typically requires from 45 to 60 minutes and
can take as long as a couple of hours. Humidity changes at an extremely slow pace towards the
end of the process. The AwE mode eliminates the tedious task of monitoring the measurements
until equilibrium has been truly reached.