DH Instruments COMPASS FOR MOLBOX, User Manual

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COMPASS

for molbox™ User’s Manual
© 1998-2003 DH Instruments, Inc .
Page 162
15.3 GAS BLENDS
Press <Create Gas Blend> in the Process Gas Editor (see Section 15) to define a blended gas.
Use the drop down list box to select the first gas in the blend. Enter the percentage of the blended gas
that the selected gas represents in the
<Add Percentage> entry field. Then press <%Add> to add the
gas percentage to the blend. Continue to select gases and enter the appropriate percentages until 100 %
of the blended gas is defined. Up to five gases can be used to define a gas blend. Then press
<OK> to
update the Process Gas Editor with the newly defined blend. Press <Clear> to erase all process gas
information. Use the control box <X> or the <Esc> key to close the display without making any changes.
A nominal gas conversion factor is calculated by taking the reciprocal of the weighted reciprocal sum of
each of the component gas conversion factors. The recommended surrogate is the recommended
surrogate for the highest percentage gas (or the first gas selected if the percentages are equal).
Figure 92. <Create Gas Blend> Panel