DH Instruments COMPASS FOR MOLBOX, User Manual

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COMPASS

for molbox™ User’s Manual
© 1998-2003 DH Instruments, Inc .
Page 188
19.3 DUT SET POINTS
DUT set points are determined in almost the exact opposite manner as the DUT flow described in Section
19.2. The percentage of the DUT flow range relative to the span is used to determine the DUT output
(see Sections 8.5.4, 8.5.8 for information on DUT output and flow spans). This percentage is then
applied to the DUT set point span to determine the required set point. This calculation is used regardless
of the state of the DUT’s
<Density Correction> selection (see Section 8.5.3). The density correction is
applied to the reference flow (see Section 19.5).
The procedure for converting from the DUT flow unit to the DUT output unit is identical to the
conversion to the set point unit. In fact, all conversions between the DUT flow, output and set point
follow the same procedure. The only requirement is that the appropriate span and minimum value be
substituted into the equation.
span
current
Q
Q Q
Q
min
%
−
=
S Q S S
DUT span
= ×
+
% min
VARIABLE DESCRIPTION
Q
%
Proportion of the DUT flow span based on the measured DUT flow.
Q
current
Current DUT flow.
Q
span
DUT flow range span as determined by the difference between the
maximum and minimum flow output values in the DUT Definition.
Q
min
DUT minimum flow output defined in the DUT Definition.
S
min
DUT minimum set point defined in the DUT Definition.
S
span
DUT set point span as determined by the difference between the
maximum and minimum set points in the DUT Definition.
S
DUT
Calculated DUT set point.
19.4 DUT ERRORS
The DUT error expresses the difference between the DUT reading and the reference flow at a flow point
in a test.
Errors are calculated in four different ways: %Reading, %DUTFS, %Reading Set Point, and %DUTFS
Set point.
%Reading and %DUTFS errors express the difference between the DUT flow and the reference flow or
the DUT span. The %Reading Set Point and %DUTFS Set Point options express the difference between
the reference flow and the set point or the DUT span.