<< Click to Display Table of Contents >> Navigation:  Software > HW5 (obsolete) > General HW5 feature > Water Activity > AW measurement modes in HW5

 

The AwE / AwQuick tab is available only with HW4 Professional with AwQuick. This tab appears in the right pane of the HW5 main screen both in the Device View Mode and in the Group View Mode.

 

HW5 features two modes for measuring water activity and the name of the tab depends on which mode has been selected.

 

•AwE mode

In this mode HW5 monitors the stability of both temperature and humidity. The measurement is automatically ended as soon as both humidity and temperature reach equilibrium. 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.

 

•AwQuick mode:

In the AwQuick mode, HW5 uses an algorithm to project the full equilibrium value (water activity) of the measured product. The measurement is automatically ended and typically requires about 5 minutes.

 

HW5 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), HW5 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.

 

With the dwell time set to 4 minutes, measurements typically require about 5 minutes. When temperature conditions are stable (both at the product and probe), the measurement obtained with the AwQuick mode is generally within ± 0.005 aw of the measurement that would be obtained by waiting for full equilibration (AwE mode).