OHAUS MB45, Инструкция по эксплуатации

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How to obtain the best results - Section 8
8.5 Selection of the drying time
The Halogen Moisture Analyzer offers two different types of switch-off criteria. A switch-off criterion is understood
to mean the condition which must be met for the Halogen Moisture Analyzer to switch off automatically and end
the drying.
The first type is a timed switch-off. This is used primarily when the drying process does not attain a constant
final value and the sample continuously loses mass over time through decomposition or the evolution of difficult
to volatilize components.
The second type recognizes the end of drying automatically. The integrated balance continuously determines
the weight loss of the sample during drying. If the weight loss per unit of time is less than the set level, the
drying is stopped and the final result is displayed.
Auto Switch Off
The automatic switch-off criterion is divided into three selectable levels:
— A30 : Less than 1mg loss in 30 seconds, used for rapidly drying substances.
— A60 : Less than 1mg loss in 60 seconds, used for standard samples.
— A90 : Less than 1mg loss in 90 seconds, used for slow drying substances (e.g. plastics).
Sample weight (g)
Time
Automatic
switch-off
(level 30, 60%)
Start
t
m
AFree switch-off criterion
The Auto Free switch-off criterion is based on a user defined mean weight loss per unit of time. As soon as this
drops below the preset value, the measurement is automatically ended.
Manual
With this switch-off criterion, the measurement process continues until you stop it with the STOP button. The
elapsed time is shown in the display.
Timed switch-off
With this switch-off criterion, the measurement lasts until the preset drying time has elapsed.
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