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SEMI F56-0600 © SEMI 2000 4 14.2 MFC Indicated Flo w: () 100 ) ( % × ÷ = utput FullScaleO v OutputData low FullScaleF L L where the output data is in Column B in data sheet. Record this result in C olumn G on the data sh…
SEMI F56-0600 © SEMI 20003
13.11 Repeat Sections 13.6 through 13.9, with the
following exception: Vary the negative DC power
supply while holding the positive power supply at its
reference value.
13.12 Vary both DC power supply voltages together in
+1% steps from the reference value.
NOTE 2: If the reference voltages are ±15 V (30 V span), the
first step is a change in voltage of +0.15 V increasing the span
to +15.15 V (30.3 V span).
13.13 After the monitored signals become stable,
record the MFC zero value, the current value, and the
power supply voltage magnitudes. Record the
measurements at each step change of power level on the
data sheet. Continue to increase the supply voltage
span until the MFC zero point changes by ±3% of full
scale flow, the MFC zero output point remains unstable
for five minutes, or the voltage level changes to +115%
of original value.
13.14 Return the power supply level to the original
reference value, repeat Section 13.5, and go to Section
13.13.
13.15 Repeat Section 13.11, with the following
exception: Decrement the power supply voltages by 1%
and go to Section 13.14.
13.16 Return the power supply level to the original
reference value, repeat Section 13.5, and go to Section
13.15.
13.17 Open the inlet and outlet shut-off valves that are
adjacent to the MFC (see Figure 3) and adjust the MFC
set point to 100%. Insure that all reference conditions
are within the specified tolerances. Once the output
signals become stable, record the MFC output signal,
the power supply voltage, the flow standard output, and
the current value.
13.18 Vary the positive DC power supply voltage in
+1% increments from the reference while holding the
negative power supply at its reference value as
described in Section 12.6. Record, on the data sheet, the
measurements of MFC flow output, power supply
voltage, flow standard output, and current meter signal
after the values become stable. Continue to increase the
voltage in 1% increments until the MFC or flow
standard signal changes by ± 3% of full scale, or the
MFC output signal remains unstable for five minutes,
or the voltage level changes to +115% of original value.
13.19 Return the power supply level to the original
reference value, repeat Section 13.5, and go to Section
13.18.
13.20 Open the inlet and outlet shut-off valves that are
adjacent to the MFC and adjust the MFC setpoint to
100%. Repeat the procedure described in Section
12.16, but decrease the positive supply voltage in 1%
decrements until either the flow signal changes by ±3%
of full scale, the MFC output signal remains unstable
for five minutes, or 85% of the original value is
reached.
13.21 Return the power supply level to the original
reference value, repeat Section 13.5, and go to Section
13.20.
13.22 Repeat Sections 13.15 through 13.19, with the
following exception: Vary the negative DC supply
voltage level while holding the positive power supply at
its reference value and go to Section 13.21.
13.23 Repeat Section 13.15 and then go to Section
13.22.
13.24 Vary both DC power supply voltages together in
+1% steps from the reference value.
NOTE 3: If the reference voltages are ± 15 V (30 V span),
then the first step is a change in voltage of +0.15 V increasing
the span to +15.15 V.
13.25 After the monitored signals become stable,
record the MFC flow and flow standard values, the
current value, and the power supply voltage
magnitudes. Record three measurements at each step-
change of power level on the data sheet. Continue to
increase the supply voltage span until either the flow
changes by ± 3% of full scale flow, the MFC zero
output point remains unstable for five minutes, or the
power level has been changed to +110% of span (±16.5
V).
13.26 Return the power supply level to the original
reference value, repeat Section 13.5, and go to Section
13.24.
13.27 Open the inlet and outlet shut-off valves that are
adjacent to the MFC and adjust the MFC setpoint to
100%. Repeat the procedure described in Section
13.22, with the following exception: Decrease the
supply voltages together in 1% decrements until either
the flow signal changes by ± 3% of full scale, the MFC
output signal remains unstable for five minutes, or until
the supply voltage span has changed ± 15% (± 12.75
V). Then go to Section 13.25.
13.28 Return the power supply level to the original
reference value, repeat Section 13.5, and go to Section
14.
14 Calculations or Interpretation of Results
14.1 Convert the MFC indicated flow output data and
the flow standard output data to percent of full scale
flow as follows:
SEMI F56-0600 © SEMI 2000 4
14.2 MFC Indicated Flow:
()
100)(% ×÷= utputFullScaleOvOutputDatalowFullScaleF LL
where the output data is in Column B in data sheet. Record this result in Column G on the data sheet.
14.3
Flow Standard (actual flow):
14.3.1 Follow the manufacturer's recommendation for the flow standard output (Column C in data sheet)
conversion to percent of full-scale flow. Record this result in Column H of the data sheet.
14.4
Calculate the average value of the three data-flow points at each power level setting for the MFC indicated
flow (Column G) and the flow standard (Column H) in the data sheet. Record the averages in Columns I and J of
the data sheet, respectively.
14.5
Determine the span by subtracting the zero value (Column G or H) at a particular power supply variation
setting from the 100% flow value (Column G or H) at the same power variation setting. These span values for the
MFC and the flow standard are to be recorded in Table 2.
settingiation
p
owersamethe
H
orColumnGavg
H
orColumnGavgSpan
MMMM
MMMM
var@
).(%0).(%100
−=
14.6
Calculate the change in flow at a power supply level by subtracting the MFC indicated value (Column I) from
the flow standard value (Column J). Record these results in Column K of the data sheet. Calculate the voltage
variation from the reference voltage value as a percent change as follows:
voltage change (VC) = voltage value - reference voltage × 100
reference voltage
Record this result in Column L and M of the data sheet for the positive and negative power supplies, respectively.
15 Reporting Results
15.1 Present the data as shown in Table 2 for both zero and span.
15.2 Present the data plots for the values in Table 2 as illustrated in Figure 4.
16 Precision and Accuracy
16.1 The precision and bias of this test method will be determined during validation.
17 Related Documents
SAMA Standard PMC 31.1-1980, Generic Test Methods for the Testing and Evaluation of Process Measurement
and Control Instrumentation.
1
IEC Publication 546-1976, Methods of Evaluating the Performance of Controller with Analogue Signals for Use in
Industrial Process Control.
2
1 Portions of this method are excerpted from SAMA Standard PMC 31.1-1980 with permission of the publisher, Process Measurement and
Control Section, SAMA, 1101 16th St., N. W., Washington, DC 20036.
2 Available from the Institute of Environmental Sciences, 940 East Northwest Highway, Mount Prospect, IL 60056.
SEMI F56-0600 © SEMI 20005
18 Illustrations
Satisfy
Manufacturers
Warm up
Requirements
Ensure all
Reference
requirements are
met
Purge MFC with
N2
Zero MFC and
record Data
Vary Positive DC
powersupply
holding negative
supply at
reference value
Record Data at
each power level
Zero MFC after
power supply limit
is reached and
record Data
Vary Negative DC
power supply
holdong positive
supply at
reference value
Record Data at
each power level
Zero MFC and
record Data
Vary both power
supplies together
and record Data
at each level of
increasing range.
Zero MFC and
record Data
Vary both power
supplies together
and record Data
at each level of
decreasing range.
Zero MFC and
record Data
Repeat 13.5 -
13.13 with MFC at
100% Flow
13.4
13.5
13.6
13.2
13.3
13.6
13.7
13.8
13.6
13.9
13.10
13.11
13.12
13.13
13.14
13.15
Figure 1
Flow Chart