1、Designation: E1256 15E1256 17Standard Test Methods forRadiation Thermometers (Single Waveband Type)1This standard is issued under the fixed designation E1256; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The test methods described in these test methods can be utilized to evaluate the following six basic operational parametersof a ra
3、diation thermometer (single waveband type):SectionCalibration Accuracy 8Repeatability 9Field-of-View 10Response Time 11Warm-Up Time 12Long-Term Stability 131.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user o
4、f this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.3 The term single waveband refers to radiation thermometers that operate in a single band of spectral radiation. This term isused to differentiate single waveb
5、and radiation thermometers from those termed as ratio radiation thermometers, two channelradiation thermometers, two color radiation thermometers, multiwavelength radiation thermometers, multichannel radiationthermometers, or multicolor radiation thermometers. The term single waveband does not precl
6、ude wideband radiationthermometers such as those operating in the 8 14 814 m band.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides
7、and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:E2758 Guide for Selection and Use of Wideband, Low Temperature Infrared Thermometers2.2 IEC DocumentsIEC/TS 62492-1 ed 1.0 TS Industrial Process Control Dev
8、icesRadiation ThermometersPart 1: Technical Data for RadiationThermometers3. Terminology3.1 Definitions:3.1.1 blackbody, nthe perfect or ideal source of thermal radiant power having a spectral distribution described by the Planckequation.3.1.1.1 DiscussionThe term blackbody is often used to describe
9、 a furnace or other source of radiant power which approximates the ideal.3.1.2 center wavelength, na wavelength, usually near the middle of the band of radiant power over which a radiationthermometer responds, that is used to characterize its performance.1 These test methods are under the jurisdicti
10、on of ASTM Committee E20 on Temperature Measurement and are the direct responsibility of Subcommittee E20.02 onRadiation Thermometry.Current edition approved July 1, 2015May 1, 2017. Published July 2015June 2017. Originally approved in 1988. Last previous edition approved in 20112015 asE1256 11a.E12
11、56 15. DOI: 10.1520/E1256-15.10.1520/E1256-17.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately
12、, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.
13、1.2.1 DiscussionThe value of the center wavelength is usually specified by the manufacturer of the instrument.3.1.3 field-of-view, na usually circular, flat surface of a measured object from which the radiation thermometer receivesradiation.2NOTE 1Field-of-view traditionally has been referred to as
14、target size.3.1.4 measuring distance, ndistance or distance range between the radiation thermometer and the target (measured object) forwhich the radiation thermometer is designed.2NOTE 2Measuring distance traditionally has been referred to as target distance.3.1.5 radiation thermometer, na radiomet
15、er calibrated to indicate the temperature of a blackbody.3.1.6 radiometer, na device for measuring radiant power that has an output proportional to the intensity of the input power.3.1.7 target distance, nsee measuring distance.3.1.8 target plane, nthe plane, perpendicular to the line of sight of a
16、radiation thermometer, that is in focus for that instrument.3.1.9 target size, nsee field-of-view.3.2 Definitions of Terms Specific to This Standard:3.2.1 reference temperature source, na source of thermal radiant power of known temperature or emissivity, or both, used inthe testing of radiation the
17、rmometers.3.2.2 temperature resolution, nthe minimum simulated or actual change in target temperature that gives a usable change inoutput or indication, or both.4. Significance and Use4.1 The purpose of these test methods is to establish consensus test methods by which both manufacturers and end use
18、rs mayperform tests to establish the validity of the readings of their radiation thermometers. The test results can also serve as standardperformance criteria for instrument evaluation or selection, or both.4.2 The goal is to provide test methods that are reliable and can be performed by a sufficien
19、tly skilled end user or manufacturer.It is hoped that it will result in a better understanding of the operation of radiation thermometers and also promote improvedcommunication between the manufacturers and the end users. A user without sufficient knowledge and experience should seekassistance from
20、the equipment makers or other expert sources, such as those found at the National Institute of Standards andTechnology in Gaithersburg, Maryland.4.3 These test methods should be used with the awareness that there are other parameters, particularly spectral range limits andtemperature resolution, whi
21、ch impact the use and characterization of radiation thermometers and for which test methods have notyet been developed.4.3.1 Temperature resolution is the minimum simulated or actual change in target temperature that results in a usable changein output or indication, or both. It is usually expressed
22、 as a temperature differential or a percent of full-scale value, or both, andusually applies to value measured. The magnitude of the temperature resolution depends upon a combination of four factors:detector noise equivalent temperature difference (NETD), electronic signal processing, signal-to-nois
23、e characteristics (includingamplification noise), and analog-to-digital conversion “granularity.”4.3.2 Spectral range limits are the upper and lower limits to the wavelength band of radiant energy to which the instrumentresponds. These limits are generally expressed in micrometers (m) and include th
24、e effects of all elements in the measuring opticalpath. At the spectral response limits, the transmission of the measuring optics is 5 % of peak transmission. (See Fig. 1.)5. Apparatus5.1 The following apparatus, set up as illustrated in Fig. 2, can be used to perform the standard tests for all six
25、parameters.5.1.1 Reference Temperature SourceA blackbody (or other stable isothermal radiant source of high and known emissivity)with an opening diameter at least as large as that specified in these test methods.NOTE 3Typical examples include nearly isothermal furnaces with internal geometries, such
26、 as a sphere with an opening small relative to its radius,or a right circular cylinder with one end closed having a radius small relative to its length.35.1.2 Temperature IndicatorEither contact or radiometric, which accurately displays the temperature of the referencetemperature source.2 IEC 62492-
27、1.3 DeWitt, D. P., and Nutter, G. D., eds., “Theory and Practice of Radiation Thermometry,” John Wiley and Sons, New York, NY.E1256 1725.1.3 Shutter MechanismOf sufficient size so as to completely block the opening of the reference temperature source from thefield-of-view of the test instrument. The
28、 shutter mechanism shall activate within a time interval that is short when compared withthe response time of the test instrument.5.1.4 Iris DiaphragmOf sufficient size so that when fully open the iris diameter is greater than the opening of the referencetemperature source. It shall be located with
29、its opening concentric with and perpendicular to the line of sight of the radiationthermometer.5.1.4.1 The side of the diaphragm facing the radiation thermometer should be blackened (nearly nonreflective) so as to minimizethe effect of radiation reflected from the surrounding environment. In additio
30、n the iris should be shaded from sources of intenseextraneous radiation. (See Note 11.)5.1.5 Aperture SetIf an iris diaphragm is not available, an aperture disc set of appropriate diameters can be used. Each apertureshould be blackened and also mounted and protected from extraneous sources of radiat
31、ion as discussed in 5.1.4.1.5.1.6 Data Acquisition SystemsOf appropriate speed and storage capacity to measure and record the output signal of theradiation thermometer in Section 10, Response (“Response Time Test Method.Method”).5.1.7 Power SupplyCapable of supplying the proper voltage and frequency
32、, if necessary, to the radiation thermometer.6. Calibration Accuracy Test Method6.1 SummaryThis test method outlines the procedure to be used to evaluate the maximum deviation between the temperatureindicated by the radiation thermometer and the known temperature of a reference temperature source, i
33、ncluding the uncertainty ofthe reference temperature source relative to the current International Temperature Scale.6.2 Test Conditions:6.2.1 Rated supply voltage and frequency.6.2.2 Prescribed warm-up period.6.2.3 After execution of internal standardization check (if available).6.2.4 Emissivity com
34、pensation set to one (1).6.2.5 Minimum opening of the reference temperature source shall not obstruct the field-of-view of the radiation thermometerwith the test aperture as specified by the manufacturer.6.2.6 Laboratory ambient temperature range of 20 C to 25 C.6.2.7 The manufacturer shall specify
35、any special conditions such as atmospheric absorption effects, measuring distance, and soforth.6.2.8 The manufacturer shall specify the output for determining the indicated temperature.6.3 Test Method:6.3.1 The radiation thermometer is sighted at the reference temperature source whose temperature is
36、 sequentially stabilized atthree calibration points distributed uniformly over the measurement range of the instrument.6.3.2 The temperature of the reference temperature source and the temperature indicated by the radiation thermometer arerecorded, then the difference between the two values is calcu
37、lated and recorded. (See Fig. 3.)6.3.3 The test sequence is repeated twice for the same three calibration points, and an average temperature difference iscalculated and recorded for each calibration point.6.4 Test ResultThe value for the calibration accuracy of the temperature indication of the radi
38、ation thermometer is taken tobe the largest of the three average temperature differences determined in 6.3.2 plus or minus the uncertainty of the temperatureof the reference temperature source relative to the current International Temperature Scale.FIG. 1 Spectral Range LimitsE1256 173NOTE 4The cali
39、bration accuracy is generally expressed as a temperature difference or a percent of full-scale value, or both.NOTE 5The value applies across the entire measurement range.NOTE 6If the reference temperature source is measured with other than a calibrated reference or secondary standard radiation therm
40、ometer, then theemissivity of the source enters into the calibration of the test radiation thermometer.7. Procedure7.1 Detailed directions for evaluation of each parameter listed in 1.1 are included in each parameter test method.7.2 Each parameter test method is organized by: parameter term, summary
41、, test conditions, test method, test result, andapplicable notes.FIG. 2 Test Method ApparatusFIG. 3 Worksheet for Calibration Accuracy Test MethodE1256 1748. Repeatability Test Method8.1 SummaryThis test method outlines the procedure to be used to evaluate the repeatability of the temperature indica
42、tion ofa radiation thermometer for a number of consecutive measurements made under the same conditions over a specified interval oftime.8.2 Test Conditions:8.2.1 Rated supply of voltage and frequency.8.2.2 Prescribed warm-up period.8.2.3 After execution of internal standardization check (if availabl
43、e).8.2.4 Diameter of the reference temperature source opening shall be greater than the radiation thermometer field-of-view, asspecified by the manufacturer.8.2.5 Laboratory ambient temperature range of 20 C to 25 C.8.2.6 Emissivity compensation, if any, set to one (1).8.2.7 The manufacturer shall s
44、pecify any special conditions such as response time, atmospheric absorption effects, measuringdistance, and so forth.8.3 Test Method:8.3.1 Once a day for twelve consecutive working days, the radiation thermometer is sighted at the reference temperature sourcewhose temperature is stabilized at the ap
45、proximate midpoint of the radiation thermometer calibration range.NOTE 7The selected reference temperature source temperature shall be reproduced for each of the twelve consecutive tests.8.3.2 The temperature of the reference temperature source and the temperature(s) indicated by the radiation therm
46、ometer duringeach days test are recorded.8.3.3 The radiation thermometer shall be switched off after each series of measurements.8.4 Test ResultThe value for the repeatability of the readings of the radiation thermometer is taken to be the standard deviationof the twelve recorded readings.S.D.5!(i51
47、N Xi 2X! 2N 21 5!(i51N Xi 2 2S(i51NXi D2NN 21where:S.D. = standard deviation,N = number of measurements,Xi = value of the ith measurement, andX =average of the twelve measurements 5(i51N XiN .NOTE 8The repeatability of the temperature indication is generally expressed as a temperature difference or
48、a percent of full-scale value, or both.NOTE 9The value for the repeatability can be applied across the entire measuring temperature range, or, the same test can be performed at otherselected temperatures across the measuring temperature range in order to assess the repeatability of the radiation the
49、rmometer at those temperatures.9. FieldofViewField-of-View Test Method9.1 SummaryThis test method outlines the procedure to be used to evaluate the diameter of the circle located in the targetplane of the reference temperature source, at a known distance along and perpendicular to a radiation thermometers line of sight,and from which 99 % of the radiant power received by the radiation thermometer is collected. (See Figs. 3 and 4.)9.2 Test Conditions:9.2.1 Rated supply voltage and frequency.FIG. 4 Field-of-View versus Measurin
