1、Designation: E2309/E2309M 05 (Reapproved 2011)1Standard Practices forVerification of Displacement Measuring Systems andDevices Used in Material Testing Machines1This standard is issued under the fixed designation E2309/E2309M; the number immediately following the designation indicates the yearof ori
2、ginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEThe units statement (1.3) and the designation were editorially revise
3、d in January 2011.1. Scope1.1 These practices cover procedures and requirements forthe calibration and verification of displacement measuringsystems by means of standard calibration devices for static andquasi-static testing machines. This practice is not intended tobe complete purchase specificatio
4、ns for testing machines ordisplacement measuring systems. Displacement measuringsystems are not intended to be used for the determination ofstrain. See Practice E83.1.2 These procedures apply to the verification of the dis-placement measuring systems associated with the testingmachine, such as a sca
5、le, dial, marked or unmarked recorderchart, digital display, etc. In all cases the buyer/owner/usermust designate the displacement-measuring system(s) to beverified.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system
6、may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 Displacement values indicated on displays/printouts oftesting machine data systemsbe they instantaneous, delayed,store
7、d, or retransmittedwhich are within the Classificationcriteria listed in Table 1, comply with Practices E2309/E2309M.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priat
8、e safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E83 Practice for Verification and Classification of Exten-someter Systems3. Terminology3.1 Definitions:3.1.1 accuracy, ndegree of conformity of a measure t
9、o astandard.3.1.2 error, nthe amount of deviation from a standard.3.1.2.1 DiscussionThe word “error” shall be used withnumerical values, for example, “At a displacement of +1.00 in.,the error of the displacement measuring system was +0.001in.”3.1.3 tolerance, nthe allowable deviation from a standard
10、.3.2 Definitions of Terms Specific to This Standard:3.2.1 calibration, nin the case of displacement measuringsystems used with testing machines, the process of comparingthe displacement indication of the machine or system under testto that of a standard, making adjustments as needed to meeterror req
11、uirements.3.2.2 capacity range, nin the case of testing machines, therange of displacement for which it is designed. Some testingmachines have more than one capacity range, that is, multipleranges.3.2.3 correction, nin the case of a testing machine, thedifference obtained by subtracting the measured
12、 displacementfrom the correct value of the applied displacement.3.2.4 displacement, na movement or measurement oflength expressed in terms of millimeters, inches, etc.3.2.5 displacement measuring system, na device or set ofdevices comprised of a displacement transducer and associatedinstrumentation.
13、1These practices are under the jurisdiction of ASTM Committee E28 onMechanical Testing and is the direct responsibility of Subcommittee E28.01 onCalibration of Mechanical Testing Machines and Apparatus.Current edition approved Jan. 15, 2011. Published January 2011. Originallypublished in 2005. Last
14、previous edition approved in 2005 as E2309-05. DOI:10.1520/E2309-05R11E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe
15、ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.6 lower limit of verification range, nthe lowest valueof displacement at which a displacement measuring system canbe verified.3.2.7 percent error, nin the case of a dis
16、placement mea-suring system, the ratio, expressed as a percent, of the error tothe correct value of the applied displacement.3.2.7.1 DiscussionThe measured displacement, as mea-sured by the testing machine, and the applied displacement, ascomputed from the readings of the verification device, shall
17、berecorded at each verification displacement data point. Theerror, and the percent error, shall be calculated from this data asfollows:Error 5 A 2 BPercent Error 5 A 2 B!/B# 3 100where:A = displacement measured by the machine being verified,mm in., andB = correct value of the applied displacement, m
18、m in., asdetermined by the calibration device.3.2.8 reference standard, na standard used to measuredisplacement applied by the testing machine and measured bythe displacement measuring system to be verified.3.2.9 resolution of the displacement indicator, nsmallestchange of displacement that can be e
19、stimated or ascertained onthe displacement measuring apparatus of the testing machine orsystem, at any applied displacement. Appendix X1 describes amethod for determining resolution.3.2.10 resolution of analog type displacement indicators(scales, dials, recorders, etc.), nthe resolution is the small
20、estchange in displacement indicated by a displacement of apointer, or pen line. The resolution is calculated by multiplyingthe displacement corresponding to one graduation by the ratioof the width of the pointer or pen line to the center to centerdistance between two adjacent graduation marks.3.2.11
21、 resolution of digital type displacement indicators(numeric, displays, printouts, etc.), nthe resolution is thesmallest change in displacement that can be displayed on thedisplacement indicator, at any applied displacement. AppendixX1 describes a method for determining resolution.3.2.11.1 Discussion
22、If the displacement indication, foreither type of displacement indicator, fluctuates by more thantwice the resolution, as described in 3.2.9 or 3.2.10, theresolution, expressed as displacement, shall be equal to one-half the range of the fluctuation.3.2.12 relative repeatability, nthe closeness of t
23、he agree-ment between the results of successive measurements from thesame applied displacement, carried out under the same condi-tions of measurement. It is expressed as percentage of the meanindicated output for the same applied displacement on twosuccessive calibrations for the given displacement.
24、3.2.13 relative reversibility, nthe difference between themean measured displacement obtained for a given applieddisplacement applied in an increasing mode and the meanindicated displacement obtained for the same given displace-ment applied in a decreasing mode.3.2.14 testing machine, na mechanical
25、device for apply-ing force and displacement to a specimen.3.2.14.1 DiscussionThe instrumentation may be either anelectrical or a mechanical device, that is, a scale or pointersystem.3.2.15 verification, nin the case of displacement measur-ing systems used with testing machines, the process of com-pa
26、ring the displacement indication of the machine or systemunder test to that of a standard and reporting results, withoutmaking adjustments.3.2.16 verification displacement, na displacement withtraceability derived from national standards of length with aspecific uncertainty of measurement, which can
27、 be applied todisplacement measuring systems.3.2.17 verified range of displacement, nin the case oftesting machines, the range of measured displacement forwhich the testing machine gives results within the permissiblevariations specified.4. Significance and Use4.1 Testing machines that apply and mea
28、sure displacementare used in many industries. They may be used in researchlaboratories to determine material properties, and in productionlines to qualify products for shipment. The displacementmeasuring devices integral to the testing machines may be usedfor measurement of crosshead or actuator dis
29、placement over adefined range of operation. The accuracy of the displacementvalue shall be traceable to the National Institute of Standardsand Technology (NIST) or another recognized National Labo-ratory. Practices E2309 provides a procedure to verify thesemachines and systems, in order that the mea
30、sured displacementvalues may be traceable. A key element to having traceabilityis that the devices used in the verification produce knowndisplacement characteristics, and have been calibrated in ac-cordance with adequate calibration standards.5. Calibration Devices5.1 Reference standards used for ca
31、libration and or verifi-cation of displacement measuring systems shall have estimatedmeasurement uncertainties. The reported uncertainty of refer-ence standards must be equal to or less than13 the allowableerror for the measuring system Classification as shown in TableTABLE 1 Classification of Displ
32、acement Measuring SystemsClassificationResolution not to Exceed the Greater of: Error not to Exceed the Greater of:Fixed Error, mm in. % of Reading Fixed Error, mm in.Relative Error(% of Displacement)Class A 0.013 0.0005 60.25 60.025 0.001 60.5Class B 0.038 0.0015 60.5 60.075 0.003 61.0Class C 0.064
33、 0.0025 61.0 60.125 0.005 62.0Class D 0.13 0.005 61.5 60.25 0.010 63.0E2309/E2309M 05 (2011)121. The estimated measurement uncertainty of the referencestandard should have a confidence level of 95 % (k = 2).6. System Verification6.1 Displacement measuring systems shall be verified as asystem with th
34、e displacement sensing and measuring devices(see 1.2 and 1.4) in place and operating as in actual use.6.2 System verification is invalid if the displacement sens-ing devices are removed and checked independently of thetesting machine.6.3 A Practices E2309 verification consists of at least twoverific
35、ation runs of displacement contained in the displacementrange(s) selected. See 8.1 and 8.2.6.3.1 If the initial verification run produces values withinthe Practices E2309 requirements of Section 15, the data maybe used “as found” for run one of the two required for the newverification report.6.3.2 I
36、f the initial verification run produces any valueswhich are outside of the Practices E2309 requirements, the “asfound” data may be reported and may be used in accordancewith applicable quality control programs.6.3.3 Calibration adjustments may be made to improve theaccuracy of the system. They shall
37、 be followed by the tworequired verification runs, and issuance of a new verificationreport.7. Application of Displacement7.1 In the verification of the displacement measuring sys-tem, approach the displacement test value by applying the testdisplacement from a lower value of displacement. To reduce
38、the error in displacement measurement due to internal backlashof the testing machine, associated fixtures and or apparatus,make sure to approach the starting zero position of the testingmachine from a point less than zero and in the direction forwhich the resultant verification data will be acquired
39、. Thisprocedure shall be followed when acquiring descending veri-fication data as well. When acquiring descending verificationdata apply a displacement greater than the starting point andadjust the testing machine to re-establish a starting zeroposition in the direction for which verification data i
40、s to beacquired.7.2 Displacement measuring systems that are used to ac-quire test data in both ascending and descending directions,shall be verified in both directions.8. Selection of Verification Displacement Values8.1 For any displacement range, verify the displacementmeasuring system by applying
41、at least five test displacementvalues, at least two times, with the difference between any twosuccessive displacement value applications being no largerthan one-third the difference between the selected maximumand minimum test displacement values. Applied displacementvalues on the second run are to
42、be approximately the same asthose on the first run. Report all values.8.2 The low limit of displacement measurement must beequal to or greater than:400 times the resolution for Class A200 times the resolution for Class B100 times the resolution for Class C67 times the resolution for Class D8.2.1 Whe
43、re the resolution of the displacement measuringsystem is sufficient to allow for verification below 10 % ofdisplacement capacity or range, verify the displacement rangeby applying at least two successive series of displacementvalues, arranged in overlapping decade groups, such that themaximum displa
44、cement value in one decade is the minimumdisplacement value in the next higher decade. Starting with theselected minimal displacement value in each decade, there areto be at least five displacement applications, in an approximateratio of 1:1, 2.5:1, 5:1, 7.5:1, and 10:1, unless the maximumdisplaceme
45、nt value is reached prior to completing all displace-ment application ratios. Report all displacement values andtheir percent errors.NOTE 1Example: If full scale is 200 mm 8 in. and the minimalresolution is 0.025 mm 0.001 mm, the minimum verified displacementwould be 5 mm (0.025 3 200). Two decades
46、of 20 and 200 mm could beselected to cover the displacement application range. Suitable verificationtest displacement values would then be approximately 5, 10, 15, 20, 50,100, 150, 200 mm. The largest reported error of the two sets of the testruns is the maximum error for the displacement range.9. P
47、reliminary Procedure9.1 Alignment:9.1.1 When fixturing the calibration device, it is importantto minimize any misalignment. Significant errors can beinduced due to misalignment. Gauge blocks or a square may beused to ensure that the calibration device operates parallel tothe actuator in hydraulic te
48、sting machines or perpendicular tothe crosshead in electro-mechanical testing machines.9.2 Temperature Considerations:9.2.1 Where the displacement measuring systems are elec-trical, connect the displacement transducer, indicator, interface,etc. using the appropriate cabling used in the actual machin
49、esetup. Turn on power and allow the components to warm up fora period of time recommended by the manufacturer. In theabsence of any recommendations, allow at least 15 min for thecomponents to be energized.9.2.2 Position a temperature measuring device in closeproximity to the machine being verified. Allow the displace-ment measuring device and all relevant parts of the verificationequipment to reach thermal stability.9.2.3 Include any bias due to temperature effects in theexpanded uncertainty statement associated with the ve
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