SIST EN 60534-9:2008
Industrial-process control valves -- Part 9: Test procedure for response measurements from step inputs
Industrial-process control valves -- Part 9: Test procedure for response measurements from step inputs
This part of IEC 60534 defines the testing and reporting of the step response of control valves that are used in throttling closed-loop control applications. A control valve consists of the complete, ready-to-use assembly of the control valve body, the actuator, and any required accessories. The most probable accessory is a valve positioner. The object of this standard is to define how to test, measure, and report control valve response characteristics in an open-loop environment. This information can be used for process control applications to determine how well and how fast the control valve responds to the control valve input signal. This standard does not define the acceptable control valve performance for process control nor does it restrict the selection of control valves for any application. If this standard is used for evaluation or acceptance testing, the parties may agree to documented variations from these requirements. The information using the defined test methods is specifically applicable to closed-loop feedback control but may have some application to open-loop control applications. It does not address valves used in on-off control service. Tests specified in this standard may not be sufficient to measure the performance required for all applications. Not all control valve applications will require this testing.
Stellventile für die Prozessregelung -- Teil 9: Prüfverfahren zur Bestimmung des Verhaltens von Stellventilen bei Sprungfunktionen
Vannes de régulation des processus industriels -- Partie 9: Procédure d’essai pour la mesure de la réponse des vannes de régulation à des signaux d’entrée échelonnés
Elle définit les essais et les rapports d'essai relatifs à la réponse à un échelon des vannes de régulation utilisées dans les applications de commande en boucle de régulation fermée. Une vanne de régulation consiste en un assemblage complet, prêt à l'emploi, d'un corps de vanne de régulation, d'un actionneur et de tout autre accessoire requis. L'accessoire le plus fréquent est un positionneur de vanne. Elle définit également comment réaliser les essais, les mesures et le rapport relatifs aux caractéristiques de la réponse des vannes de régulation dans un environnement en boucle ouverte. Cette information peut être utilisée pour des applications de commande de processus afin de déterminer comment et avec quelle rapidité la vanne de régulation répond au signal d'entrée de commande de la vanne. Le contenu du corrigendum de juin 2008 a été pris en considération dans cet exemplaire.
Regulacijski ventili za industrijske procese - 9. del: Preskusni postopki za meritve odziva na stopnico (IEC 60534-9:2007)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 60534-9:2008
01-februar-2008
Regulacijski ventili za industrijske procese - 9. del: Preskusni postopki za meritve
odziva na stopnico (IEC 60534-9:2007)
Industrial-process control valves -- Part 9: Test procedure for response measurements
from step inputs
Stellventile für die Prozessregelung -- Teil 9: Prüfverfahren zur Bestimmung des
Verhaltens von Stellventilen bei Sprungfunktionen
Vannes de régulation des processus industriels -- Partie 9: Procédure d’essai pour la
mesure de la réponse des vannes de régulation à des signaux d’entrée échelonnés
Ta slovenski standard je istoveten z: EN 60534-9:2007
ICS:
23.060.40 7ODþQLUHJXODWRUML Pressure regulators
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
SIST EN 60534-9:2008 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN STANDARD
EN 60534-9
NORME EUROPÉENNE
October 2007
EUROPÄISCHE NORM
ICS 23.060; 25.040.40
English version
Industrial-process control valves -
Part 9: Test procedure for response measurements from step inputs
(IEC 60534-9:2007)
Vannes de régulation Stellventile für die Prozessregelung -
des processus industriels - Teil 9: Prüfverfahren zur Bestimmung
Partie 9: Procédure d’essai des Verhaltens von Stellventilen
pour la mesure de la réponse bei Sprungfunktionen
des vannes de régulation (IEC 60534-9:2007)
à des signaux d’entrée échelonnés
(CEI 60534-9:2007)
This European Standard was approved by CENELEC on 2007-10-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60534-9:2007 E
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EN 60534-9:2007 - 2 -
Foreword
The text of document 65B/632/FDIS, future edition 1 of IEC 60534-9, prepared by SC 65B, Devices &
process analysis, of IEC TC 65, Industrial-process measurement, control and automation, was submitted
to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60534-9 on 2007-10-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2008-07-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2010-10-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60534-9:2007 was approved by CENELEC as a European
Standard without any modification.
__________
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- 3 - EN 60534-9:2007
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year
1) 2)
IEC 60534-1 – Industrial-process control valves - EN 60534-1 2005
Part 1: Control valve terminology and general
considerations
1) 2)
IEC 60534-4 – Industrial process control valves - EN 60534-4 2006
Part 4: Inspection and routine testing
1)
Undated reference.
2)
Valid edition at date of issue.
---------------------- Page: 4 ----------------------
IEC 60534-9
Edition 1.0 2007-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial-process control valves –
Part 9: Test procedure for response measurements from step inputs
Vannes de régulation des processus industriels –
Partie 9: Procédure d’essai pour la mesure de la réponse des vannes de
régulation à des signaux d’entrée échelonnés
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
U
CODE PRIX
ICS 23.060; 25.040.40 ISBN 2-8318-9280-5
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– 2 – 60534-9 © IEC:2007
CONTENTS
FOREWORD.3
1 Scope and object.5
2 Normative references .5
3 Terms and definitions.5
4 Symbols .10
5 General test procedures .11
5.1 Test valve conditions.11
5.2 Test system.11
5.3 Measuring instruments .11
5.4 Process variable.12
5.5 Nominal test position.13
6 Examples of step response.13
7 Tests specified for each of three test environments .15
7.1 Bench tests .15
7.2 Laboratory tests .16
7.3 In-process tests.16
8 Detailed test procedures.17
8.1 Baseline test .17
8.2 Small-step test .18
8.3 Response-time tests.19
9 Presentation of test results.21
9.1 General information.21
9.2 Test results .22
9.2.1 Baseline test.22
9.2.2 Small-step test .22
9.2.3 Response-time tests.22
Annex A (informative) Sliding friction measurement .24
Bibliography.26
Figure 1 – Dead band and resolution .6
Figure 2 – Typical step change and response without overshoot.14
Figure 3 – Step response with some overshoot.15
Figure 4 – Example step and response during baseline test.18
Figure 5 – Signal sequence for small-step test.19
Figure 6 – Sample signal step sequence for response time tests .20
Figure 7 – Sample data from small-step test (Δs = 0,13 %) performed in a process loop .23
Figure 8 – Sample plot showing step response, t , versus step size for four different
86
valves .23
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60534-9 © IEC:2007 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
INDUSTRIAL-PROCESS CONTROL VALVES –
Part 9: Test procedure for response measurements from step inputs
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60534-9 has been prepared by subcommittee 65B: Devices, of IEC
technical committee 65: Industrial-process measurement and control.
The text of this standard is based on the following documents:
FDIS Report on voting
65B/632/FDIS 65B/639/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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– 4 – 60534-9 © IEC:2007
The list of all the parts of the IEC 60634 series, under the general title Industrial-process
control valves, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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60534-9 © IEC:2007 – 5 –
INDUSTRIAL-PROCESS CONTROL VALVES –
Part 9: Test procedure for response measurements from step inputs
1 Scope and object
This part of IEC 60534 defines the testing and reporting of the step response of control valves
that are used in throttling closed-loop control applications. A control valve consists of the
complete, ready-to-use assembly of the control valve body, the actuator, and any required
accessories. The most probable accessory is a valve positioner.
1
NOTE For background, refer to technical report ANSI/ISA-TR75.25.02 [6] .
The object of this standard is to define how to test, measure, and report control valve
response characteristics in an open-loop environment. This information can be used for
process control applications to determine how well and how fast the control valve responds to
the control valve input signal.
This standard does not define the acceptable control valve performance for process control
nor does it restrict the selection of control valves for any application. If this standard is used
for evaluation or acceptance testing, the parties may agree to documented variations from
these requirements.
The information using the defined test methods is specifically applicable to closed-loop
feedback control but may have some application to open-loop control applications. It does not
address valves used in on-off control service.
Tests specified in this standard may not be sufficient to measure the performance required for
all applications. Not all control valve applications will require this testing.
2 Normative references
The following documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the
referenced document (including any amendments) applies.
IEC 60534-1, Industrial-process control valves – Part 1: Control valve terminology and
general consideration
IEC 60534-4, Industrial-process control valves – Part 4: Inspection and routine testing
3 Terms and definitions
For the purposes of this document, the following terms and definitions, as well as those given
in IEC 60534-1 and other parts of IEC 60534, apply.
NOTE 1 In the specific area of non-linear dynamics, it was determined that some terms defined in IEC 60050-351
or in [5] lacked the precision desired for these documents. Others were inconsistent with the terminology used in
the non-linear control literature.
—————————
1
Figures in square brackets refer to the Bibliography.
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– 6 – 60534-9 © IEC:2007
NOTE 2 Reference [6] explains applicable terms and explores control valve static and dynamic response
characteristics important for process control. That information will aid correct interpretation and application of the
test results obtained from the tests defined in this standard.
Output
b
a c
d
a < resolution ≤ b
Input
c < dead band ≤ d
Time
Dynamics are not shown
IEC 1630/07
Figure 1 – Dead band and resolution
3.1
closed-loop time constant
time constant of the closed-loop response of a control loop, used in tuning methods such as
Internal Model Control (IMC) and Lambda Tuning and is a measure of the performance of a
control loop
3.2
dead band
finite range of values within reversal of the input variable does not produce any noticeable
change in the output variable
[IEC 60534-4, 3.2]
3.3
dead time
time interval between the instant when a variation of an input variable is produced and the
instant when the consequent variation of the output variable starts
3.4
dynamic response
time-dependent output signal change resulting from a defined time-dependent input signal
change
NOTE Commonly used input signal changes include impulse, pulse, step, ramp, and sinusoid [4]. Dynamic means
that the control valve is moving. Dynamic response can be measured without process loading in bench-top tests,
with simulated or active loading in a flow laboratory or under normal process operating conditions.
Amplitude
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60534-9 © IEC:2007 – 7 –
3.5
gain ratio
G
R
response gain G divided by the response gain G determined from the multi-step test
Z Z02
performed with a step size of 2 %. The ideal gain ratio equals 1,0 for tests about any nominal
position
G = G /G
R Z Z02
NOTE Measuring the gain ratio may not be possible if a digital positioner with pulse-modulated output is involved
in the system since, on such positioners, the gain measurement may give infinite values.
3.6
input step size
Δs
difference between the beginning and ending signal in a step change expressed as a per cent
of the signal span
3.7
limit cycle
oscillation caused by the non-linear behaviour of a feedback system
NOTE 1 These oscillations are of fixed amplitude and frequency and can be sustained in a feedback loop even if
the system input change is zero. In linear systems, an unstable oscillation grows theoretically to infinite amplitude,
but non-linear effects limit this growth [3].
NOTE 2 The occurrence of the limit cycle may be dependent on current valve position.
3.8
non-linear system
system whose response depends on the amplitude and the nature of the input signal, as well
as the initial conditions of the system. As an example, a non-linear system can change from
being stable to unstable by changing the size of the input signal
NOTE When a non-linear system is driven towards a set point by feedback control action, it is likely to develop a
limit cycle. The amplitude and frequency of such limit cycles are a function of the nature of the non-linearities
which are present, and the effective gain of the feedback control action. As the gain of the feedback is increased,
the frequency of the limit cycle is likely to increase. More aggressive gain increases may produce behaviour such
as bifurcation, frequency doubling and eventually chaotic behaviour.
3.9
overshoot
for a step response, the maximum transient deviation from the final steady-state value of the
output variable, expressed as a percentage of the difference between the final and the initial
steady-state values
3.10
relative travel
h
ratio of the travel at a given opening to the rated travel
[IEC 60534-1, 4.5.4]
3.11
resolution
smallest step increment of input signal in one direction for which movement of the output is
observed, expressed as a percentage of the input span
NOTE The term “valve resolution” in this standard means the tendency of a control valve to move in finite steps in
responding to step changes in the input signal applied in the same direction. This happens when the control valve
sticks in place, having stopped moving after the previous step change.
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– 8 – 60534-9 © IEC:2007
3.12
step response
time history of a variable after a step change in the input. In this standard, the step response
can be stem position, flow, or another process variable
3.13
response flow coefficient
C
R
apparent flow coefficient as determined by testing in an operating type environment. The data
available in the operating environment may differ from the laboratory data required by valve
sizing standards
NOTE 1 Flow coefficients in current use are K and C depending upon the system of units. For further
v v
information, refer to IEC 60534-1.
NOTE 2 It will be noted that the dimensions and units on each of the following defined flow coefficients are
different. However, it is possible to relate these flow coefficients numerically. This relationship is as follows:
K
v
= 0,865
C
v
3.14
response gain
G
Z
ratio of the steady-state magnitude of the process change, ΔZ, divided by the signal step, Δs,
that caused the change. One special reference response gain is defined as that calculated
from the 2 % step size response time test which is designated as G
Z02
G = ΔZ/Δs
Z
G = ΔZ /Δs
Z02 02 02
3.15
sampling interval
Δt
s
time increment between sampled data points which is the inverse of the sampling rate,
f
0
Δt = 1/f
S
0
NOTE As used in this standard, since more than one variable is being sampled, it is the time between the sets of
sampled data. Ideally, all variables in one set are sampled at the same time. If data is recorded using analogue
equipment, the time constant for the recording equipment should be less than, or equal to, the maximum allowed
Δt .
s
3.16
sampling rate
f
0
rate at which data samples are taken or the number of samples per unit time (see 3.15)
3.17
sliding friction
F or T
R R
force or torque required to maintain motion in either direction at a prescribed input signal
ramp rate
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60534-9 © IEC:2007 – 9 –
3.18
static
means without motion or change [4]; readings are recorded after the device has come to rest.
Static performance can be measured either without process loading (bench-top tests), with
simulated or active loading, or under process operating conditions
NOTE This kind of test is sometimes called a dynamic test [4] which may cause confusion. The static behaviour
characteristics identified as important to the control valve performance are the dead band, the resolution, and the
valve travel gain.
3.19
steady state
state of a system which is maintained after all transient effects have subsided as long as all
input variables remain constant
3.20
step change
nearly instantaneous step change made to an input signal of a dynamic system with the
intention of stimulating a step response of the dynamic system. Such a test is used to
characterize the step response of the dynamic system
3.21
step change time
Δt
sc
time between the start of a signal input step and attainment of its maximum value
3.22
step test
application of a step change to an input signal in order to test the step response dynamics
3.23
step response time
t
86
interval of time between initiation of an input signal step change and the moment that the
response of a dynamic reaches 86,5 % of its full steady-state value. The step response time
includes the dead time before the dynamic response
3.24
stiction (static friction)
resistance to the start of motion, usually measured as the difference between the driving
values required to overcome static friction upscale and downscale [5]
3.25
time constant
τ
time required to complete 63,2% (i.e. 1-1/e) of the total change of the output of a first-order
linear system produced by a step-wise variation of the input variable
NOTE The term is used in this standard to describe the dynamic characteristics of the analogue measuring
instruments.
3.26
valve travel gain
change in closure member position divided by the change in input signal, both expressed in
percentage of full span
G = ΔX/Δs
X
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– 10 – 60534-9 © IEC:2007
3.27
valve system approximate time constant
τ'
time constant of a first-order response without dead time, which may fit the actual control
valve step response reasonably well. The approximate time constant is defined to provide a
basis for comparison of the valve with other time constants, such as the closed-loop time
constant for the control loop
NOTE 1 A first-order system reaches 86,5 % of its final step response value in two time constants; the
approximate time constant is considered to be one-half of the step response time, t .
86
NOTE 2 The use of the approximate time constant in no way implies that the response of the control valve is first-
order. The step response of the control valve is typically complex, having dead time initially, followed by potentially
complex dynamics before the steady state is achieved. t includes the dead time in the initial part of the response,
86
as well as the possibility of slower settling in the last portion of the response. Some valve positioner designs
attempt to achieve a slow-down in the final part of the response in order to limit overshoot. τ' attempts to produce a
simple linear time constant approximation of the control-valve dynamic response, which can be compared to the
closed-loop time constant of the control loop on the same basis in time-constant units. It should be noted that as
the portion of t that is dead time increases, this approximation becomes less ideal.
86
3.28
wait time
Δt
w
time spent after a step input change waiting for the response to come to the new steady-state
value
3.29
X-Y plot
plot of the output excursions plotted against input excursions. Input-output plots are useful for
defining the steady-state characteristics of non-linearities
4 Symbols
Symbol Description Unit
C Response flow coefficient (K or C ) Various
R v v
(see IEC 60534-1)
Δs Input step size % of input range
Reference input step size of 2 % % of input range
Δs02
Sample interval s
Δt
s
Δt Step change time s
sc
Δt Wait time s
W
Change of closure member position % rated travel
ΔX
ΔZ Process variable change % of process output
ΔZ Process variable change at 2 % input change % of process output
02
f Sampling rate 1/s
0
F Friction force N
R
G
R Gain ratio 1
G Valve travel gain 1
X
G Response gain 1
Z
G Response gain at 2 % step input 1
z02
n
down Number of steps (falling signal) in a response time test sequence 1
n Number of steps (rising signal) in a response time test sequence 1
up
h Relative travel %
τ Time constant s
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60534-9 © IEC:2007 – 11 –
Symbol Description Unit
T Friction torque Nm
R
t Step response time s
86
t
86B Base response time s
t Step response time (increasing signal) s
861
t Step response time (decreasing signal) s
862
t Dead time s
d
5 General test procedures
5.1 Test valve conditions
The test valve shall be set to its desired test configuration. This includes configuring the valve
assembly with the desired packing type and condition, the positioner if applicable, and the
actuator configuration. The positioner configuration shall include any applicable adjustments
or parameters (at digital positioners). In some cases, preliminary tests may be performed
such as testing to assure there is no excessive overshoot. (Excessive overshoot is not
defined here and the amount allowed may vary according to the application but shall be
reported.) All applicable characteristics of the valve configuration that would affect test
results shall be reported (see 7.1)
5.2 Test system
Testing to determine the response of a control valve requires a signal generator or source and
instruments to measure the input signal, the position of the closure member and, for
laboratory testing or in-process testing, the desired response variable. The response variable
could be derived from other variables that may need to be measured as well.
The tests can be performed manually with appropriate instrumentation but computers are
recommended for all, or at least part, of the testing and analyses.
When measuring response time, data shall be co
...
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