Instruction Manual

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 47 of 51
© 2006; Rotronic AG IN-E-HyLab-V4_11
The AwE mode runs simultaneously for all probes connected to the HygroLab. When a probe is
done, the HygroLab beeps once and freezes the display for that probe. The display can be
manually switched to another probe from the keypad with the ▼ or ▲ arrow.
When the last probe is done
, press the ENTER key to exit this screen and return to the standard
mode.
Press ENTER again to start a new measurement in the AwE mode with all probes.
Important
: unlike the equivalent function of the HW4 software, the HygroLab 3 does not allow to
start and stop each probe individually. To avoid possible confusion, you may want to either
disconnect or turn off any unused probe.
17.6 Using the AwQuick mode (HygroLab 3)
In the AwQuick mode, the HygroLab 3 uses an algorithm to project the full equilibrium value (water
activity) of the product sample. The measurement is automatically ended and typically requires
about 5 minutes.
The HygroLab 3 performs the following tasks:
1) the value of the humidity signal is constantly monitored
2) the stability of the temperature signal is constantly monitored
3) After an initial period of time (dwell time), the HygroLab uses the humidity data to project the end
value
of the equilibration process (water activity). The measurement ends automatically as soon as
the projected Aw value is stable. At that time, the HygroLab makes a short beep and freezes
the display. The RS 232 output keeps being updated.
With the default dwell time of 4 minutes, measurements typically require about 5 minutes. The
difference between the AwQuick mode and the Standard mode is typically 0.005 aw or less.
The value of the dwell time can be set by the user (see Mode). This value represents a trade off
between speed of measurement and accuracy. Generally, a longer dwell time produces more
accurate results but causes measurements to take longer.
The value of temperature is the average temperature during the measurement. The HygroLab
displays a trend indicator next to the value of temperature. This is used to verify that temperature is
stable during the measurement.