1、Designation: E1256 15Standard 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 revision. A num
2、ber 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 beutilized to evaluate the following six basic operational param-eters of a radiation
3、 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 thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this s
4、tandard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.3 The term single waveband refers to radiation thermom-eters that operate in a single band of spectral radiation. Thisterm is used to differentiate single waveband
5、radiation ther-mometers from those termed as ratio radiation thermometers,two channel radiation thermometers, two color radiationthermometers, multiwavelength radiation thermometers, mul-tichannel radiation thermometers, or multicolor radiation ther-mometers. The term single waveband does not preclu
6、dewideband radiation thermometers such as those operating inthe814mband.2. Referenced Documents2.1 ASTM Standards:E2758 Guide for Selection and Use of Wideband, LowTemperature Infrared Thermometers2.2 IEC DocumentsIEC/TS 62492-1 ed 1.0 TS Industrial Process ControlDevicesRadiation ThermometersPart 1
7、: TechnicalData for Radiation Thermometers3. Terminology3.1 Definitions:3.1.1 blackbody, nthe perfect or ideal source of thermalradiant power having a spectral distribution described by thePlanck equation.3.1.1.1 DiscussionThe term blackbody is often used todescribe a furnace or other source of radi
8、ant power whichapproximates the ideal.3.1.2 center wavelength, na wavelength, usually near themiddle of the band of radiant power over which a radiationthermometer responds, that is used to characterize its perfor-mance.3.1.2.1 DiscussionThe value of the center wavelength isusually specified by the
9、manufacturer of the instrument.3.1.3 field-of-view, na usually circular, flat surface of ameasured object from which the radiation thermometer re-ceives radiation.2NOTE 1Field-of-view traditionally has been referred to as target size.3.1.4 measuring distance, ndistance or distance rangebetween the r
10、adiation thermometer and the target (measuredobject) for which the radiation thermometer is designed.2NOTE 2Measuring distance traditionally has been referred to as targetdistance.3.1.5 radiation thermometer, na radiometer calibrated toindicate the temperature of a blackbody.3.1.6 radiometer, na dev
11、ice for measuring radiant powerthat has an output proportional to the intensity of the inputpower.3.1.7 target distance, nsee measuring distance.3.1.8 target plane, nthe plane, perpendicular to the line ofsight of a radiation thermometer, that is in focus for thatinstrument.3.1.9 target size, nsee f
12、ield-of-view.3.2 Definitions of Terms Specific to This Standard:3.2.1 reference temperature source, na source of thermalradiant power of known temperature or emissivity, or both,used in the testing of radiation thermometers.3.2.2 temperature resolution, nthe minimum simulated oractual change in targ
13、et temperature that gives a usable changein output or indication, or both.1These test methods are under the jurisdiction of ASTM Committee E20 onTemperature Measurement and are the direct responsibility of Subcommittee E20.02on Radiation Thermometry.Current edition approved July 1, 2015. Published J
14、uly 2015. Originally approvedin 1988. Last previous edition approved in 2011 as E1256 11a. DOI: 10.1520/E1256-15.2IEC 62492-1.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Significance and Use4.1 The purpose of these test methods
15、 is to establishconsensus test methods by which both manufacturers and endusers may perform tests to establish the validity of the readingsof their radiation thermometers. The test results can also serveas standard performance criteria for instrument evaluation orselection, or both.4.2 The goal is t
16、o provide test methods that are reliable andcan be performed by a sufficiently skilled end user or manu-facturer. It is hoped that it will result in a better understandingof the operation of radiation thermometers and also promoteimproved communication between the manufacturers and theend users. A u
17、ser without sufficient knowledge and experienceshould seek assistance from the equipment makers or otherexpert sources, such as those found at the National Institute ofStandards and Technology in Gaithersburg, Maryland.4.3 These test methods should be used with the awarenessthat there are other para
18、meters, particularly spectral rangelimits and temperature resolution, which impact the use andcharacterization of radiation thermometers and for which testmethods have not yet been developed.4.3.1 Temperature resolution is the minimum simulated oractual change in target temperature that results in a
19、 usablechange in output or indication, or both. It is usually expressedas a temperature differential or a percent of full-scale value, orboth, and usually applies to value measured. The magnitude ofthe temperature resolution depends upon a combination of fourfactors: detector noise equivalent temper
20、ature difference(NETD), electronic signal processing, signal-to-noise charac-teristics (including amplification noise), and analog-to-digitalconversion “granularity.”4.3.2 Spectral range limits are the upper and lower limits tothe wavelength band of radiant energy to which the instrumentresponds. Th
21、ese limits are generally expressed in micrometers(m) and include the effects of all elements in the measuringoptical path.At the spectral response limits, the transmission ofthe measuring optics is 5 % of peak transmission. (See Fig. 1.)5. Apparatus5.1 The following apparatus, set up as illustrated
22、in Fig. 2,can be used to perform the standard tests for all six parameters.5.1.1 Reference Temperature SourceA blackbody (orother stable isothermal radiant source of high and knownemissivity) with an opening diameter at least as large as thatspecified in these test methods.NOTE 3Typical examples inc
23、lude nearly isothermal furnaces withinternal geometries, such as a sphere with an opening small relative to itsradius, or a right circular cylinder with one end closed having a radiussmall relative to its length.35.1.2 Temperature IndicatorEither contact or radiometric,which accurately displays the
24、temperature of the referencetemperature source.5.1.3 Shutter MechanismOf sufficient size so as to com-pletely block the opening of the reference temperature sourcefrom the field-of-view of the test instrument. The shuttermechanism shall activate within a time interval that is shortwhen compared with
25、 the response time of the test instrument.5.1.4 Iris DiaphragmOf sufficient size so that when fullyopen the iris diameter is greater than the opening of thereference temperature source. It shall be located with itsopening concentric with and perpendicular to the line of sightof the radiation thermom
26、eter.5.1.4.1 The side of the diaphragm facing the radiationthermometer should be blackened (nearly nonreflective) so asto minimize the effect of radiation reflected from the surround-ing environment. In addition the iris should be shaded fromsources of intense extraneous radiation. (See Note 11.)5.1
27、.5 Aperture SetIf an iris diaphragm is not available, anaperture disc set of appropriate diameters can be used. Eachaperture should be blackened and also mounted and protectedfrom extraneous sources of radiation as discussed in 5.1.4.1.5.1.6 Data Acquisition SystemsOf appropriate speed andstorage ca
28、pacity to measure and record the output signal of theradiation thermometer in Section 10, Response Time TestMethod.5.1.7 Power SupplyCapable of supplying the proper volt-age and frequency, if necessary, to the radiation thermometer.6. Calibration Accuracy Test Method6.1 SummaryThis test method outli
29、nes the procedure to beused to evaluate the maximum deviation between the tempera-ture indicated by the radiation thermometer and the knowntemperature of a reference temperature source, including theuncertainty of the reference temperature source relative to thecurrent International Temperature Scal
30、e.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 (ifavailable).6.2.4 Emissivity compensation set to one (1).3DeWitt, D. P., and Nutter, G. D., eds., “Theory and Practice of RadiationThermometry,” Jo
31、hn Wiley and Sons, New York, NY.FIG. 1 Spectral Range LimitsE1256 1526.2.5 Minimum opening of the reference temperature sourceshall not obstruct the field-of-view of the radiation thermom-eter with the test aperture as specified by the manufacturer.6.2.6 Laboratory ambient temperature range of 20 to
32、 25 C.6.2.7 The manufacturer shall specify any special conditionssuch as atmospheric absorption effects, measuring distance,and so forth.6.2.8 The manufacturer shall specify the output for deter-mining the indicated temperature.6.3 Test Method:6.3.1 The radiation thermometer is sighted at the refere
33、ncetemperature source whose temperature is sequentially stabi-lized at three calibration points distributed uniformly over themeasurement range of the instrument.6.3.2 The temperature of the reference temperature sourceand the temperature indicated by the radiation thermometer arerecorded, then the
34、difference between the two values iscalculated and recorded. (See Fig. 3.)6.3.3 The test sequence is repeated twice for the same threecalibration points, and an average temperature difference iscalculated and recorded for each calibration point.6.4 Test ResultThe value for the calibration accuracy o
35、fthe temperature indication of the radiation thermometer istaken to be the largest of the three average temperaturedifferences determined in 6.3.2 plus or minus the uncertainty ofthe temperature of the reference temperature source relative tothe current International Temperature Scale.NOTE 4The cali
36、bration accuracy is generally expressed as a tempera-ture 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 otherthan a calibrated reference or secondary standard radiation therm
37、ometer,then the emissivity of the source enters into the calibration of the testradiation thermometer.7. Procedure7.1 Detailed directions for evaluation of each parameterlisted in 1.1 are included in each parameter test method.7.2 Each parameter test method is organized by: parameterterm, summary, t
38、est conditions, test method, test result, andapplicable notes.8. Repeatability Test Method8.1 SummaryThis test method outlines the procedure to beused to evaluate the repeatability of the temperature indicationof a radiation thermometer for a number of consecutivemeasurements made under the same con
39、ditions over a specifiedinterval of time.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 (ifavailable).8.2.4 Diameter of the reference temperature source openingshall be greater than the radiation
40、 thermometer field-of-view,as specified by the manufacturer.8.2.5 Laboratory ambient temperature range of 20 to 25 C.8.2.6 Emissivity compensation, if any, set to one (1).8.2.7 The manufacturer shall specify any special conditionssuch as response time, atmospheric absorption effects, measur-ing dist
41、ance, and so forth.8.3 Test Method:8.3.1 Once a day for twelve consecutive working days, theradiation thermometer is sighted at the reference temperaturesource whose temperature is stabilized at the approximatemidpoint of the radiation thermometer calibration range.NOTE 7The selected reference tempe
42、rature source temperature shallFIG. 2 Test Method ApparatusE1256 153be reproduced for each of the twelve consecutive tests.8.3.2 The temperature of the reference temperature sourceand the temperature(s) indicated by the radiation thermometerduring each days test are recorded.8.3.3 The radiation ther
43、mometer shall be switched off aftereach series of measurements.8.4 Test ResultThe value for the repeatability of thereadings of the radiation thermometer is taken to be thestandard deviation of the twelve recorded readings.S.D. 5!(i51NXi2 X!2N 2 15!(i51NXi22S(i51NXiD2NN 2 1where:S.D. = standard devi
44、ation,N = number of measurements,Xi= value of the ith measurement, andX=average of the twelve measurements 5(i51NXiN.NOTE 8The repeatability of the temperature indication is generallyexpressed as a temperature difference or a percent of full-scale value, orboth.NOTE 9The value for the repeatability
45、can be applied across the entiremeasuring temperature range, or, the same test can be performed at otherselected temperatures across the measuring temperature range in order toassess the repeatability of the radiation thermometer at those temperatures.9. FieldofView Test Method9.1 SummaryThis test m
46、ethod outlines the procedure to beused to evaluate the diameter of the circle located in the targetplane of the reference temperature source, at a known distancealong and perpendicular to a radiation thermometers line ofsight, and from which 99 % of the radiant power received bythe radiation thermom
47、eter is collected. (See Figs. 3 and 4.)9.2 Test Conditions:9.2.1 Rated supply voltage and frequency.9.2.2 Prescribed warm-up period.9.2.3 After execution of internal standardization check (ifapplicable).9.2.4 Laboratory ambient temperature range of 20 to 25 C.9.2.5 Minimum opening of the reference t
48、emperature sourceshall be large enough so as to not obstruct the optical path ofthe radiation thermometer, as specified by the manufacturer,when it is sighted through an aperture that is twice the diameterof the instruments field-of-view at the plane of the aperture.NOTE 10Some radiation thermometer
49、s have a field-of-view so largethat a commercially available reference temperature source cannot beused; a separate test method is under preparation for use in such cases.9.2.6 Manufacturer shall specify any special conditionssuch as atmospheric absorption effects, measuring distance,how and when to clean the radiation thermometer lens, and soforth.9.3 Test Method:9.3.1 The temperature of the reference temperature source isstabilized at a value near the top of the calibration range of theradiation thermometer.9.3.2 The iris is posit
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