semi合集-English.pdf - 第413页

SEMI E56-1104 © SEMI 1996, 2004 2 5.1.12 DBS — dea dband of setpoint 5.1.13 D l — lower de adband value 5.1.14 D u — upper deadband val ue 5.1.15 DUT — device under test 5.1.16 FS — full scale flow rate 5.1.17 HD — hyste…

100%1 / 7923
SEMI E56-1104 © SEMI 1996, 2004 1
SEMI E56-1104
TEST METHOD FOR DETERMINING ACCURACY, LINEARITY,
REPEATABILITY, SHORT-TERM REPRODUCIBILITY, HYSTERESIS,
AND DEADBAND OF THERMAL MASS FLOW CONTROLLERS
This test method was technically approved by the Global Gases Committee and is the direct responsibility of
the North American Gases Committee. Current edition approved by the North American Regional Standards
Committee on July 11, 2004. Initially available at www.semi.org September 2004; to be published
November 2004. Originally published December 1996.
1 Purpose
1.1 The purpose of this document is to provide a
standardized method to quantify the accuracy, linearity,
repeatability, short-term reproducibility, hysteresis, and
deadband of a thermal mass flow controller.
1.2 The intent of this document is not to suggest any
specific testing program but to specify the test method
to be used when testing for parameters that are covered
by this method. The user might use this document to
check significant performance characteristics such as
accuracy, precison, bias, repeatability, linearity, short-
term reproducibility, and deadband under a set of
closely controlled test conditions.
1.3 The significance of the accuracy calculations in
this method is to allow an MFC user to transfer a
process from one manufacturing tool to another and to
exchange MFCs within a single manufacturing tool
while maintaining process control.
2 Scope
2.1 This document describes the conditions and
procedures for testing the accuracy, linearity,
repeatability, hysteresis, and deadband of thermal mass
flow controllers (MFCs). Because of the generic nature
of this document, not all test procedures apply to all
types of MFCs.
2.2 This document provided a common basis for
communication between manufacturers and users.
NOTICE: This standard does not purport to address
safety issues, if any, associated with its use. It is the
responsibility of the users of this standard to establish
appropriate safety and health practices and determine
the applicability of regulatory or other limitations prior
to use.
3 Limitations
3.1 It is not practical to evaluate performance under all
possible combinations of operating conditions. This
test procedure should be applied under laboratory
conditions; its intent is to collect sufficient data to form
a judgement of the field performance of the MFC being
tested.
4 Referenced Standards
4.1 SEMI Standard
SEMI E17 — Guideline for Mass Flow Controller
Transient Characteristics Tests
4.2 ASME Standard
1
ASME MFC-10M — Method for Establishing
Installation Effects on Flowmeters
4.3 ISA Standard
2
ISA S51.1 — Process Instrumentation Terminology
NOTICE: Unless otherwise indicated, all documents
cited shall be the latest published versions.
5 Terminology
5.1 Abbreviations & Acronyms
5.1.1 A — Measured Value
5.1.2 A
a
— average measured value
5.1.3 A
a
— average measured value at 100% setpoint
5.1.4 AD — accuracy of the DUT
5.1.5 AD
f
— accuracy of the flow standard
5.1.6 AS — accuracy of setpoint
5.1.7 A
l
— measured value, down cycle
5.1.8 A
u
— measured value, up cycle
5.1.9 B — bias
5.1.10 D — deadband value
5.1.11 DBD — deadband of device
1 American Society of Mechanical Engineers, Three Park Avenue,
New York, NY 10016-5990, USA. Telephone: 800.843.2763
(U.S./Canada), 95.800.843.2763 (Mexico), 973.882.1167 (outside
North America), Website: www.asme.org
2 Instrument Society of America, 67 Alexander Drive, Research
Triangle Park, NC 27709, USA Telephone: 919.549.8411 Website:
www.isa.org
SEMI E56-1104 © SEMI 1996, 2004 2
5.1.12 DBS — deadband of setpoint
5.1.13 D
l
— lower deadband value
5.1.14 D
u
— upper deadband value
5.1.15 DUT — device under test
5.1.16 FS — full scale flow rate
5.1.17 HD — hysteresis of device
5.1.18 HDBS — hysteresis plus deadband at a setpoint
5.1.19 HS — hysteresis at a setpoint
5.1.20 i — reading number in a cycle for a given set-
point
5.1.21 I — intermediate value
5.1.22 j — cycle for a given setpoint
5.1.23 k — up cycle number for a given setpoint
5.1.24 kPa — kilopascal
5.1.25 LD — linearity of DUT
5.1.26 LS — linearity of setpoint
5.1.27 m — slope
5.1.28 m — down cycle number for a setpoint
5.1.29 n — number of up scale readings
5.1.30 NC — normally closed
5.1.31 n
j
— number of readings at a setpoint at a given
cycle
5.1.32 NO — normally open
5.1.33 P — precision
5.1.34 psia — pounds per square inch absolute
5.1.35 RPD — repeatability of the DUT
5.1.36 RPS — repeatability at a setpoint
5.1.37 S — setpoint
5.1.38 S
a
— average of setpoint
5.1.39 sccm — standard cubic centimeters per minute
5.1.40 S
l
— setpoint, down cycle
5.1.41 S
u
— setpoint, up cycle
5.1.42 slm — standard liters per minute
5.1.43 SRD — short-term reproducibility of the device
5.1.44 SRS — short-term reproducibility at a setpoint
5.1.45 v
i
— the ith measured value at a setpoint for a
given cycle
5.1.46 Y — ideal linearity value
5.1.47 Z — zero offset of DUT
5.1.48 Z
a
— indicated flow at zero actual flow
5.2 Definitions
5.2.1 accuracy — the closeness of agreement between
an observed value and the true value; the total
uncertainty of an observed value, including both
precision and bias.
5.2.2 accuracy curve — the curve fitted through the
average measured values over the specified range of the
device under test.
5.2.3 accuracy device — the total uncertainty over a
specified range of the device. Device accuracy over a
range is stated as the worst case accuracy taken over all
tested setpoints in this range.
5.2.4 actual flow — the gas flow as measured by an
external standard, not the electrical output of a mass
flow meter.
5.2.5 bias — the difference, at a setpoint, between the
measured value and the sum of the setpoint value and
the zero offset. The measured values of a flow standard
include its total uncertainty.
5.2.6 cardinal setpoint — a specific setpoint to assess
the accuracy of the device under test (DUT). For this
test method, the cardinal setpoints are 10%, 20%, 30%,
40%, 50%, 60%, 70%, 80%, 90%, and 100% of full
scale.
5.2.7 deadband — the range through which a setpoint
may be varied, upon reversal of direction, without
initiating an observable change in output signal.
5.2.8 device under test — mass flow device is being
tested by this method.
5.2.9 downscale reading — a reading approached from
a setpoint greater than the current setpoint and beyond
the deadband.
5.2.10 downscale value, average — the sum of all
downscale readings, in one cycle, at a single setpoint,
divided by the number of these values.
5.2.11 drift — the change in output over a specified
time period for a constant input under specified
reference operating conditions.
5.2.12 drift, long-term — the drift between a series of
tests over a specified time interval. This specified time
interval is generally much greater than the time
necessary to run an individual test.
5.2.13 drift, short-term — the drift between sets of
measurements over the duration of the test.
SEMI E56-1104 © SEMI 1996, 2004 3
Figure 1
Terminal-Based Linearity for Mass Flow Controller
5.2.14 hysteresis — that property of an element
evidenced by the dependence of the value of the output,
for a given excursion of the input, upon the history of
the prior excursions and the direction of the current
traverse.
5.2.15 indicated flow — flow indicated by MFC under
test. Electrical output of the DUT.
5.2.16 linearity — the closeness to which a curve
approximates a straight line.
5.2.17 linearity, terminal-based — the maximum
absolute value of the deviation of the accuracy curve
(average of upscale and downscale values) from a
straight line through the upper and lower setpoint limits
of the accuracy curve (see Figure 1).
5.2.18 measured value — the actual flow through a
device under test, expressed in sccm or slm, as
measured by a standard, preferably primary.
5.2.19 measured value, average — the sum of all
readings (both upscale and downscale) for all cycles, at
a single setpoint, divided by the number of these
readings.
5.2.20 operating conditions, normal — the range of
operating conditions within which a device is designed
to operate and for which operating influences are stated
[ISA S51.1].
5.2.21 operating conditions, reference — the range of
operating conditions of a device within which operating
influences are negligible [ISA S51.1].
5.2.22 operating influence — the change in a
performance characteristic caused by a change in a
specified operating condition from reference operating
conditions, all other conditions being held within the
limits of reference operating conditions [ISA S51.1].
5.2.23 pneumatic noise — localized, random variations
in pressure and flow.
5.2.24 precision — the closeness of agreement among
the measured values at a setpoint. It is often expressed
as a standard deviation.
5.2.25 repeatability — the closeness of agreement
among a number of measured values at a setpoint,
under the same operating conditions, operator,
apparatus, laboratory, and short intervals of time. It is
usually measured as a nonrepeatability and expressed as
a repeatability in percent of reading.
5.2.26 reproducibility — the closeness of agreement
among repeated measured values at a setpoint, within
the specified reference operating conditions, made over
a specified period of time, approached from both
directions. Reproducibility includes hysteresis,
deadband, long-term drift, and short-term
reproducibility.
NOTE 1: Between repeated measurements, the input may
vary over the range, and operating conditions may vary within
normal operating conditions.
5.2.27 reproducibility, short-term — the closeness of
agreement among a number of measured values at a
setpoint, under the same operating conditions, operator,
apparatus, laboratory and short intervals of time,
approached from both directions. The approach must