DH Instruments COMPASS FOR MOLBOX, Руководство пользователя

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COMPASS

for molbox™ User’s Manual
© 1998-2003 DH Instruments, Inc .
Page 20
5.1.3.3 RUN THE TEST
Now that the COMPASS System Configuration includes the hardware necessary
to run the test, use [Run] , [Run Test] to start a test sequence (see Section 7.2).
There is no interface selection required when setting up the DUT interface at the
end of the test initialization.
COMPASS will step through the test point sequence
gathering data from the molbox and the DUT.
5.1.4 EXAMPLE #4
“How do I set up to calibrate a rotameter?”
Typical rotameters (variable area flowmeters) have scale indications that are either in mass flow units
(sccm or slm, for example) or float position units (such as mm, inches). Since there is no electronic
output of the rotameter’s flow indication, the user must enter this value manually when a test is run.
If the rotameter’s scale is marked in flow units or unitless divisions, the reference pressure and
temperature should also be marked on the scale (or be listed in manufacturer literature).
These values must be entered into the DUT Definition as the Normal Operating Conditions of the
DUT (see Section 8.5.3).
If the scale is marked in float position units, the DUT Definition output range should be in the
same units (see Section 8.5.4).
In either case, when a test is run, the actual gas conditions at the rotameter (temperature and
absolute pressure) will need to be measured and supplied to
COMPASS .
5.1.4.1 DUT DEFINITION SETUP
Select the [Setup], [DUT], [Header] tab, and select the DUT’s process gas
(see Section 8.5.2).
Select the [Setup], [DUT, [Correction] tab, and select the “Square Root” Gas Density
Correction Type (see Section 8.5.3). You must also enter the Temperature and
Absolute Pressure for the DUT’s Normal Operating Conditions. The molecular mass
or the specific gravity and the compressibility of the process gas must also be
entered into
COMPASS in this location. If the DUT process gas is a gas that is supported
by molbox, these gas properties will be entered for you and cannot be edited.
Select the [Setup], [DUT], [Range] tab, and select or create the DUT’s Flow
Range units (these must be units of flow such as accm, or sccm – not scale indication
such as mm or inches) and enter its Flow Range (see Section 8.5.4). Enter the DUT’s
Output Range units, and enter its Output Range (these can be units such as mm or in.).
Figure 8. Example 4, DUT Setup