DH Instruments COMPASS FOR MOLBOX, User Manual

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COMPASS

for molbox™ User’s Manual
Page 153
© 1998-2003 DH Instruments, Inc .
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14.1 OVERVIEW
Flow unit of measure selection is used in COMPASS DUT Definitions (see Section 8). In all lists that
allow the selection of a flow unit of measure, there is an <Edit Units> option at the top of the list. When
<Edit Units> is selected, the <Flow Unit Editor> is displayed. In addition to this shortcut, a direct link to
the flow unit editor is available by selecting [Tools], [Flow Unit Editor] . Flow units can be created,
edited and removed using this tool.
COMPASS supports the creation of new flow units of measure by allowing the selection of a <Base Unit>
then providing the ability to change the reference pressure and temperature when applicable.
Fixed volumetrically based mass flow units as well as volume or actual flow units are available. Volume
or actual flow units require real time data acquisition of gas pressure and temperature measured at the
inlet or outlet of DUT. The actual measurement location is dependent on the DUT. User defined units
can be created by applying a multiplier to the final flow unit to change the dimension of the unit. For
example, kg/s can be changed to kg/h by using a multiplier of 3 600. Use dimensional analysis to
determine the multiplier value for example:
h
kg
s
kg
h
m
m
s
s
kg
s
kg
3600
60 60
⇒
=
See the molbox Operations and Maintenance Manual, UNIT Section for extensive information on flow
units of measure.
Flow unit of measure conversions used by COMPASS are defined in Section 19.3.