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15 Calculations or Interpretation of Results 15.1 Attitude sensitivity betwee n two mounting positions is calculated as follows: ZAS nm = Z m  Z n Where, ZAS nm = Zero attitude Sensitivity between attitude n and attitud…

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11 Safety Precautions
11.1 Follow the manufacturer’s specifications and
instructions for installation and operation whenever
possible. Note any exceptions in the test report.
12 Test Specimen
12.1 Allow all components in the test apparatus to
warm up following the manufacturer’s specification.
12.2 Take necessary steps when switching gases to
ensure that only the desired gas is in the DUT and flow
standard at the time the test is performed.
13 Preparation of Apparatus
13.1 Locate the DUT in the test environment to
stabilize temperature prior to warm up.
13.2 The reference operating conditions shall be as
follows:
13.2.1 Ambient temperature 21 ± 4 C
13.2.2 Ambient Temperature Stability Ambient
temperature to stay constant within ± 1 °C during data
acquisition period.
13.2.3 Gas temperature Same as ambient.
13.2.4 Gas pressure, Outlet Ambient Pressure
13.3 Following the conditioning period (Section 12.1)
warm up the device according to manufacturer's
specifications.
13.4 Perform an adequate purge to ensure all previous
gases and atmospheric moisture has been removed from
the system.
13.5 Leak check the test set up, using available
methodologies to verify the test system leak integrity.
13.6 The power supply must be sufficiently rated for
the device under test.
14 Procedure
14.1 Open V1 and V2. DUT and allow the flow to
stabilize. Adjust the inlet pressure to 135.8 kPa (19.7
psia).
14.2 Close the downstream isolation valve (V2); then
close the upstream isolation valve (V1), (see Figure 2).
14.3 With both isolation valves closed, and a 100%
setpoint wait until the pressure drop across the MFC is
dissipated, ensuring a “no flow” condition through the
MFC. Dissipation of the pressure across the MFC is
indicated when the indicated flow drops to a steady
state value near zero.
14.4 Once the indicated flow has dropped to a steady
value set the MFC setpoint so there is no power being
dissipated by the control valve. For a normally closed
valve this is 0% and for a normally open control valve
it is 100%.
14.5 After the electrical output signal has stabilized for
at least three minutes, record the MFC indicated zero in
Table 1.
14.6 Open V1 and V2, command 100%.
14.7 After the electrical output signal has stabilized for
at least three minutes, record the actual flow as reported
by the flow standard and the indicated flow in Table 1.
14.8 Change the attitude of the DUT to the next
desired attitude.
14.9 Close the downstream isolation valve (V2); then
close the upstream isolation valve (V1) (see Figure 2).
14.10 With both isolation valves closed, and a 100%
setpoint wait until the pressure drop across the MFC is
dissipated, ensuring a “no flow” condition through the
MFC. Dissipation of the pressure across the MFC is
indicated when the indicated flow drops to a steady
state value near zero.
14.11 Once the indicated flow has dropped to a steady
value set the MFC setpoint so there is no power being
dissipated by the control valve. For a normally closed
valve this is 0% and for a normally open control valve
it is 100%.
14.12 After the electrical output signal has stabilized
for at least three minutes, record the MFC indicated
zero in Table 1.
14.13 Open V1 and V2, command 100%.
14.14 After the electrical output signal has stabilized
for at least three minutes, record the actual flow as
reported by the flow standard and the indicated flow in
Table 1.
14.15 Repeat Sections 14.8 to 14.14 for each of the
desired attitudes.
14.16 Return the DUT to attitude 1.
14.17 Adjust the inlet pressure to 308 kPa (44.7 psia).
14.18 Repeat Sections 14.8 to 14.14.
SEMI E80-0299 © SEMI 1999, 2004 3
15 Calculations or Interpretation of Results
15.1 Attitude sensitivity between two mounting positions is calculated as follows:
ZAS
nm =
Z
m
Z
n
Where,
ZAS
nm
= Zero attitude Sensitivity between attitude n and attitude m
Z
n
= zero indication at attitude n
Z
m
= zero indication at attitude m
SAS
nm
= S
n
S
m
Where,
SAS
nm
= Span attitude Sensitivity between attitude n and attitude m
S
n
= Actual flow in attitude n
S
m
= Actual flow in attitude mZAS
max
= The maximum zero attitude sensitivity for all attitudes.
SAS
max
= The maximum span attitude sensitivity for all attitudes
15.2 Interpretation
15.2.1 Table 2 shows examples of raw and reduced data. For the MFC tested, the maximum zero shift was 0.3%
F.S. and the maximum span shift was 0.4% F.S.
Table 1 Attitude Test Data
MFC Mfg/Model/Serial # ____________________________________________
Name Plate Gas/Range ______________________________________________
Test Gas _________________________________________________________
Temp ____________________________________ Date __________________
Factory Calibration Gas _____________________________________________
Attitude Pressure
(kPa)
Indicated Flow
by DUT with
Zero Actual Flow
(% F.S.)
Zero Attitude
Sensitivity Compared
to Attitude 1
(% F.S.)
Actual Flow by Flow
Standard at 100%
DUT Setpoint
(% F.S.)
Span Attitude
Sensitivity Compared
to Attitude 1
(% F.S.)
1 135.8
0 0
2 135.8
3 135.8
4 135.8
5 135.8
ZAS
max
= SAS
max
=
1 308
0 0
2 308
3 308
4 308
5 308
ZAS
max
= SAS
max
=
SEMI E80-0299 © SEMI 1999, 2004 4
Table 2 Sample Attitude Test Data
MFC Mfg/Model/Serial # Acme/ XYZ-100/0001
Name Plate Gas/Range Nitrogen 100 sccm
Test Gas Nitrogen
Temp 20.2 C
Date 3/9/98
Factory Calibration Gas Nitrogen
Attitude Pressure
(kPa)
Indicated Flow
by DUT with
Zero Actual Flow
(% F.S.)
Zero Attitude
Sensitivity Compared
to Attitude 1
(% F.S.)
Actual Flow by Flow
Standard at 100%
DUT Setpoint
(% F.S.)
Span Attitude
Sensitivity Compared
to Attitude 1
(% F.S.)
1 135.8
0
0
100
0
2 135.8
0.1
-0.1
100.2
0.2
3 135.8
0
0
100
0
4 135.8
-0.1
0.1
99.8
-0.2
5 135.8
0
0
100
0
ZAS
max
=
0.2
SAS
max
=
0.4
1 308
0
0
100
0
2 308
0.15
-0.15
100.2
0.2
3 308
0
0
100
0
4 308
-0.15
0.15
99.8
-0.2
5 308
0
0
100
0
ZAS
max
=
0.3
SAS
max
=
0.4
NOTE 1: The values in bold italics are calculated values.
SEMI E80-0299 © SEMI 1999, 2004 5