1、BRITISH STANDARDBS EN 60534-9:2007Industrial-process control valves Part 9: Test procedure for response measurements from step inputs ICS 23.060.40; 25.040.40g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g5
2、5g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Incorporating June 2008corrigendumBS EN 60534-9:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2007 BSI 2009ISBN 978 0 580 63598 4National forewordThis British Standar
3、d is the UK implementation of EN 60534-9:2007. It isidentical IEC 60534-9:2007, incorporating corrigendum June 2008.The start and finish of text introduced or altered by corrigendum is indicated The UK participation in its preparation was entrusted Technical Committee A list of organizations represe
4、nted on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/co
5、rrigenda issued since publicationAmd. no. Date Comments31 9 Implementation of IECcorrigendum June 2008in the text by tags. Text altered by IEC corrigendum June 2008 is indicatedin the tex t by . GEL/65, Measurement and control, to Subcommittee GEL/65/2, Elements of systems.withbysubApril 200EUROPEAN
6、 STANDARD EN 60534-9NORME EUROPENNE EUROPISCHE NORM October 2007 CENELECEuropean Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2007 CENELEC - A
7、ll rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60534-9:2007 E 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 rgulationde
8、s processus industriels -Partie 9: Procdure dessaipour la mesure de la rponsedes vannes de rgulation des signaux dentre chelonns (CEI 60534-9:2007) Stellventile fr die Prozessregelung -Teil 9: Prfverfahren zur Bestimmungdes Verhaltens von Stellventilen bei Sprungfunktionen (IEC 60534-9:2007) This Eu
9、ropean 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 referen
10、ces 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 mem
11、ber 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
12、, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 60534-9:2007 2 Foreword The text of document 65B/632/FDIS, future edition 1 of IEC 60534-9, prepared by SC 65B, Device
13、s 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 confusio
14、n. 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 const
15、ant 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 tsctime between the start of a
16、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 t86interval of time between initiation of an input signal step change and the moment that the response of a dynamic
17、 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
18、downscale 5 3.25 time constant 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 measurin
19、g 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 GX= X/s 9 EN 60534-9:2007 3.27 valve system approximate time constant time constant of a first-order response without dead time, which may fit the
20、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 valu
21、e in two time constants; the approximate time constant is considered to be one-half of the step response time, t86. 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, h
22、aving dead time initially, followed by potentially complex dynamics before the steady state is achieved. t86includes the dead time in the initial part of the response, as well as the possibility of slower settling in the last portion of the response. Some valve positioner designs attempt to achieve
23、a slow-down in the final part of the response in order to limit overshoot. 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 sh
24、ould be noted that as the portion of t86that is dead time increases, this approximation becomes less ideal. 3.28 wait time tw 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 excursio
25、ns. Input-output plots are useful for defining the steady-state characteristics of non-linearities 4 Symbols Symbol Description Unit CRResponse flow coefficient (Kvor Cv) Various (see IEC 60534-1) s Input step size % of input range s02Reference input step size of 2 % % of input range tsSample interv
26、al s tscStep change time s tWWait time s X Change of closure member position % rated travel Z Process variable change % of process output Z02Process variable change at 2 % input change % of process output f0Sampling rate 1/s FRFriction force N GRGain ratio 1 GXValve travel gain 1 GZResponse gain 1 G
27、z02Response gain at 2 % step input 1 ndownNumber of steps (falling signal) in a response time test sequence 1 nupNumber of steps (rising signal) in a response time test sequence 1 h Relative travel % Time constant s EN 60534-9:2007 10 Symbol Description Unit TRFriction torque Nm t86Step response tim
28、e s t86BBase response time s t861Step response time (increasing signal) s t862Step response time (decreasing signal) s tdDead time s 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 th
29、e 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 ex
30、cessive 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 t
31、he 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
32、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 collected fast enough to give good time resolution using the requirement
33、s for the sampling interval, ts, given in equation (1). Measurement of static behaviour (dead band, gain, and resolution) generally does not depend on sample interval and can be performed using existing field instrumentation, with the sample interval reported. For a control valve with a pneumatic in
34、put signal, the input signal shall be measured as close as possible to the device input port to avoid input distortion caused by the piping. The total time for the complete input signal step change, tsc, shall meet the requirements given in equation (2). The valve position should be measured as clos
35、e as possible to the closure member or at least at a location that closely approximates the closure member position within the resolution limits given in 5.3. Care should be taken to avoid measurement errors due to excessive elastic deformation, clearances, linkages, etc. In all cases, the location
36、of measurement points shall be reported. 5.3 Measuring instruments The measurement of each output variable, which includes the combined effects of transducers, any signal conditioning equipment, and recording equipment shall meet the following minimum requirements. 2086stt or 0,5 s, whichever is les
37、s (1) 11 EN 60534-9:2007 2086sctt (2) Time constant 2086tInstrumentation used to measure the static parameters dead band, gain, and resolution need not meet these requirements but time constants, tsand tsc, shall be reported. NOTE 1 Since t86is dependent on the step size, measuring equipment with a
38、shorter time constant, , may be required on smaller step sizes. NOTE 2 For in-process tests, the flow-meter time constant should not be 2086t, unless it is used to measure t86.If installed in-process instrumentation used to measure t86does not meet these requirements, an external position transducer
39、 and recording equipment which meet the above requirements are recommended. Instrument resolution 3resolution valve,10resolution valvepreferably Inaccuracy 5 % of full-scale value, preferably 2 % of full-scale value. NOTE 3 The full-scale value is the range of the measured variable known or estimate
40、d as the control valve goes from 0 % to 100 % open. 5.4 Process variable For laboratory and in-process dead-band and resolution testing, a process variable shall be measured, if possible, in addition to the input signal and the position. Reference 6 provides guidance for choosing the best process va
41、riable out of those that may be available at a specific plant or laboratory. The response flow coefficient, CR, shown below, is a simplified flow coefficient recommended for use as the process variable, if measurement of the variables necessary to calculate it is possible. It is used here because an
42、 accurate determination of C is outside the scope of this standard and may not be feasible in many plant and in some laboratory environments. Measurements of dead band and resolution using CRwould equal those using C since changes would be equal within the typical change of input signal. This assume
43、s the flow through the control valve is fully turbulent and not choked. This response flow coefficient is calculated according to equations (3) or (4). For incompressible flow pNQC=011R(3) where Q is the liquid flow rate; 1/ois the relative density (1/o= 1,0 for water at 15 C); p is the pressure dro
44、p across the valve; N1= 1, if CRis expressed as Kvin m/h, Q in m/h and P in bar; N1= 0,865, if CRis expressed as Cvin gpm, Q in m/h and P in bar; EN 60534-9:2007 12 Or, for compressible fluid flow, 116RpxYNWC = (4) where W is the mass flow rate; p1is the upstream absolute pressure in bar; x is the p
45、ressure drop ratio 1ppx=where p is the pressure drop; TxFx31= , where F XTcan be assumed to be 0,7; N6= 31,6, if CRis expressed as Kvin m/h, W in kg/h and P in bar; N6= 27,3, if CRis expressed as Cvin gpm, Q in kg/h and P in bar NOTE If the flow through the control valve is not fully turbulent, or c
46、hoked, such as may occur during “in-process testing”, the actual C could be calculated using the normal flow equations for control valve sizing (IEC 60534-2-1). To calculate the percentage change of the process variable when using the response-flow coefficient, defined by equations (3) or (4), the m
47、aximum value of CR(at 100 % valve opening) shall be measured, estimated, or determined from manufacturer-supplied data. The value of CRat 100 % valve opening used shall be stated in the test results. The measured process variable will often fluctuate significantly during the course of the testing be
48、cause of normal fluctuations due to disturbances, etc., in the process itself or because of electrical noise in a plant environment or because of measurement noise. Curve fitting or averaging routines can therefore be applied to the data around key points such as the point where t86occurs and where
49、the total magnitude of the step change is measured. If the tests are performed manually, this may have to be done visually from a plot. In all cases, the raw data shall be plotted and if curve-fitting procedures are applied, the curve-fit data should be plotted along with the raw data. This could be used later or by others to verify calculations as required. 5.5 Nominal test position The tests shall typically be p
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