BS EN 60751:2008 BSI Standards Publication Industrial platinum resistance thermometers and platinum temperature sensors BRITISH STANDARD BS EN 60751:2008 National foreword This British Standard is the UK implementation of EN 60751:2008 It is identical to IEC 60751:2008 It supersedes BS EN 60751:1996 which is withdrawn The UK participation in its preparation was entrusted by Technical Committee GEL/65, Measurement and control, to Subcommittee GEL/65/2, Elements of systems A list of organizations represented 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 © BSI 2009 ISBN 978 580 54651 ICS 17.200.20 Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2009 Amendments issued since publication Amd No Date Text affected BS EN 60751:2008 EN 60751 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM September 2008 ICS 17.200.20 Supersedes EN 60751:1995 + A2:1995 English version Industrial platinum resistance thermometers and platinum temperature sensors (IEC 60751:2008) Thermomètres résistance de platine industriels et capteurs thermométriques en platine (CEI 60751:2008) Industrielle Platin-Widerstandsthermometer und Platin-Sensoren (IEC 60751:2008) This European Standard was approved by CENELEC on 2008-08-01 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 © 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members Ref No EN 60751:2008 E BS EN 60751:2008 –2– EN 60751:2008 Foreword The text of document 65B/664/FDIS, future edition of IEC 60751, 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 60751 on 2008-08-01 This European Standard supersedes EN 60751:1995 + A2:1995 The significant technical changes with respect to EN 60751:1995 are as follows: While the temperature/resistance relationship in 4.2 remains unchanged, there are several changes in the other chapters Most important are: – tolerance classes follow a new scheme; – tolerance acceptance test is included; – hysteresis test is included; – several changes in the individual tests; – appendices are deleted 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) 2009-05-01 – latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2011-08-01 Annex ZA has been added by CENELEC Endorsement notice The text of the International Standard IEC 60751:2008 was approved by CENELEC as a European Standard without any modification BS EN 60751:2008 EN 60751:2008 –3– 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 IEC 61152 (mod) - 1) Dimensions of metal-sheathed thermometer elements EN 61152 1994 2) IEC 61298-1 - 1) Process measurement and control devices General methods and procedures for evaluating performance Part 1: General considerations EN 61298-1 1995 2) 1) 2) Undated reference Valid edition at date of issue –2– BS EN 60751:2008 60751  IEC:2008 CONTENTS FOREWORD Scope .6 Normative references .6 Terms and definitions .6 Characteristics 4.1 Temperature/resistance relationships 4.2 Resistance values General requirements 12 5.1 Tolerance classes 12 5.1.1 Temperature range of validity 12 5.1.2 Resistors 12 5.1.3 Thermometers 12 5.1.4 Special tolerance classes and special temperature ranges of validity 12 5.2 Measuring current 13 5.3 Electrical supply 13 5.4 Connecting wire configuration 13 Tests 14 6.1 6.2 6.3 6.4 6.5 6.6 General 14 6.1.1 Routine production tests 14 6.1.2 Type tests 14 6.1.3 Additional type tests 14 Routine production tests for resistors 14 6.2.1 Tolerance acceptance test 14 Routine production tests for thermometers 15 6.3.1 Insulation resistance at ambient temperature 15 6.3.2 Sheath integrity test 15 6.3.3 Dimensional test 16 6.3.4 Tolerance acceptance test 16 Type tests for resistors 16 6.4.1 Tolerances 16 6.4.2 Stability at upper temperature limit 16 6.4.3 Self-heating 16 Type tests for thermometers 16 6.5.1 Insulation resistance at elevated temperatures 16 6.5.2 Thermal response time 18 6.5.3 Stability at upper temperature limit 18 6.5.4 Thermoelectric effect 18 6.5.5 Effect of temperature cycling 18 6.5.6 Effect of hysteresis 18 6.5.7 Self-heating 18 6.5.8 Minimum immersion depth 19 Additional type tests for special applications of thermometers 19 6.6.1 Capacitance 19 6.6.2 Inductance 19 6.6.3 Dielectric strength 19 6.6.4 Vibration test 19 BS EN 60751:2008 60751  IEC:2008 –3– 6.6.5 Drop test 19 6.7 Summary of tests 19 Information to be made available by the manufacturer 20 7.1 For resistors only 20 7.2 For resistors and/or thermometers 20 Thermometer identification and marking 20 Figure – Connecting configurations 13 Figure – Examples of test results for selecting or rejecting resistors 15 Table – Temperature/resistance relationship, R = 100.00 Ω 10 Table – Tolerance classes for resistors 12 Table – Tolerance classes for thermometers 12 Table – Minimum insulation resistance of thermometers at maximum temperature 16 Table – Table of tests described in this standard 20 –4– BS EN 60751:2008 60751  IEC:2008 INTERNATIONAL ELECTROTECHNICAL COMMISSION INDUSTRIAL PLATINUM RESISTANCE THERMOMETERS AND PLATINUM TEMPERATURE SENSORS 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 nongovernmental 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 60751 has been prepared by subcommittee 65B: Devices and process analysis, of IEC technical committee 65: Industrial-process measurement, control and automation This second edition cancels and replaces the first edition published in 1983, amendment (1986) and amendment (1995) This edition constitutes a technical revision The significant technical changes with respect to the previous edition are as follows: While the temperature/resistance relationship in 4.2 remains unchanged, there are several changes in the other chapters Most important are: – tolerance classes follow a new scheme; – tolerance acceptance test is included; – hysteresis test is included; – several changes in the individual tests; – appendices are deleted BS EN 60751:2008 60751  IEC:2008 –5– The text of this standard is based on the following documents: FDIS Report on voting 65B/664/FDIS 65B/683/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 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 –6– BS EN 60751:2008 60751  IEC:2008 INDUSTRIAL PLATINUM RESISTANCE THERMOMETERS AND PLATINUM TEMPERATURE SENSORS Scope This standard specifies the requirements and temperature/resistance relationship for industrial platinum resistance temperature sensors later referred to as “platinum resistors” or "resistors" and industrial platinum resistance thermometers later referred to as "thermometers" whose electrical resistance is a defined function of temperature The International Standard applies to platinum resistors whose temperature coefficient α, defined as α= R 100 − R R ⋅ 100 °C is conventionally written as α = 3.851 x 10 –3 °C –1 , where R 100 is the resistance at t = 100 °C and R is the resistance at t = °C Values of temperature in this standard are in terms of the International Temperature Scale of 1990, ITS-90 Temperatures in degrees Celsius are denoted by the symbol t, except in Table where the full nomenclature t 90 /°C is used The standard covers resistors or thermometers for all or part of the temperature range -200 °C to +850 °C with different tolerance classes, which may cover restricted temperature ranges For temperature/resistance relationships with uncertainties 0.2 m/s The self-heating under the above mentioned conditions shall not exceed 25 % of the tolerance value of the declared tolerance class at the declared maximum measuring current 6.5 6.5.1 Type tests for thermometers Insulation resistance at elevated temperatures The insulation resistance shall be tested with the thermometer being at the rated maximum temperature over at least the minimum immersion depth and a test voltage minimum of 10 V d.c The insulation resistance between each terminal and the sheath shall not be less than indicated in Table Table – Minimum insulation resistance of thermometers at maximum temperature Rated maximum temperature Minimum insulation resistance °C MΩ BS EN 60751:2008 60751  IEC:2008 – 17 – up to 250 20 251 to 450 451 to 650 0.5 651 to 850 0.2 – 18 – 6.5.2 BS EN 60751:2008 60751  IEC:2008 Thermal response time The thermal response time τ0.5 in flowing water with a velocity >0.2 m/s and/or in flowing air with a velocity (3 ± 0.3) m/s shall be recorded If requested the response times τ0.9 and/or τ 0.1 may also be recorded 6.5.3 Stability at upper temperature limit After a minimum of weeks (672 h) continuously maintained at the specified upper temperature limit, the drift of the resistance value of the thermometer at °C shall be not more than the tolerance value of the declared tolerance class The insulation resistance shall not be less than specified in 6.5.1 6.5.4 Thermoelectric effect The thermometer shall be heated to the declared maximum temperature with the thermometer terminals close to the ambient temperature The immersion depth of the thermometer shall be varied until the EMF is at its maximum Set the direct measuring current to the maximum permissible value and obtain resistance readings with the normal and reversed polarity of the current The temperature equivalent of the difference between the resistance of the thermometer measured with the normal and reversed polarity of the current shall not exceed the tolerance value of the declared tolerance class 6.5.5 Effect of temperature cycling The thermometer shall be brought carefully to the upper limit of its temperature range and then exposed to air at room temperature It shall next be brought slowly to the lower limit of its temperature range and then exposed to air at room temperature At each limit, the thermometer shall be immersed to at least its declared minimum immersion depth and shall be maintained at the temperature for sufficient time to reach equilibrium After 10 cycles between the upper and the lower temperature limits, the calibration at °C shall not drift by more than the tolerance value at °C for the respective tolerance class 6.5.6 Effect of hysteresis The resistance of the thermometer shall be measured in the middle of the temperature range after exposure to a temperature at the lower limit of the temperature range Then the resistance should be measured again at the same temperature in the middle of the temperature range after exposure of the thermometer to a temperature at the upper limit of the temperature range The difference between these two measurements shall not be larger than the calculated tolerance value at the test temperature for the respective tolerance class It is important for both measurements that the thermometer goes directly from the ends of the temperature range to the temperature in the middle of range EXAMPLE : If the range of the thermometer is °C to 400 °C, the thermometer shall go from °C to 200 °C, then from 200 °C to 400 °C, and finally from 400 °C to 200 °C without cooling below 200 °C during this last step 6.5.7 Self-heating The self-heating coefficient expressed in °C/mW shall be evaluated at a temperature between °C and 30 °C in flowing water with a velocity >0.2 m/s and/or in flowing air with a velocity of (3 ± 0.3) m/s The self-heating under the above mentioned conditions shall not exceed 25 % of the tolerance value of the declared tolerance class at the declared maximum measuring current BS EN 60751:2008 60751  IEC:2008 6.5.8 – 19 – Minimum immersion depth The thermometer shall be immersed into water with a temperature of at least 85 °C to the same depth as used for the tolerance acceptance test and with the thermometer terminals close to the ambient temperature The thermometer shall then be extracted step by step out of the medium until the resistance changes by an amount which corresponds to a temperature change of 0.1 °C This immersion depth shall be declared as minimum immersion depth 6.6 Additional type tests for special applications of thermometers For particular applications, special type tests may be agreed between user and manufacturer, for example: 6.6.1 Capacitance The capacitance between one terminal and the sheath at a frequency of kHz is to be reported 6.6.2 Inductance The inductance of each resistor circuit at a frequency of kHz is to be reported 6.6.3 Dielectric strength A test voltage of 500 V a.c shall be applied between one measuring circuit and the sheath of the thermometer for a duration of During this time no breakdown shall occur For thermometers with two or more measuring circuits, the same test shall be made between the individual circuits 6.6.4 Vibration test This test should be conducted if possible with the thermometer mounted in the same manner as that in which it is to be used The thermometer shall be vibrated over the frequency range of 10 Hz to 500 Hz with a forcing acceleration of 20 m/s to 30 m/s The frequency range shall be swept at a rate of one octave per minute for a total period of 150 h The vibrations shall be applied to the thermometer in axial and transverse directions each for one-half of the total period The frequency and nature of any resonance shall be noted and limited to the first harmonic The electrical continuity shall be monitored continuously At the conclusion of this test, the thermometer shall be tested to ensure the continued compliance with the insulation resistance requirements of 6.3.1 The thermometer shall also be tested to verify that the resistance at °C shall not have changed by more than the equivalent of 0.1 °C 6.6.5 Drop test This test is intended to reveal any weakness of construction The thermometer, complete with head, if any, shall be held with its longitudinal axis horizontal and then be dropped ten times from the height of 250 mm on to a mm thick steel plate on a rigid floor The thermometer shall be inspected for mechanical damage It shall also be tested to ensure continued compliance with the insulation resistance requirements of 6.3.1 and the maintenance of electrical continuity 6.7 Summary of tests The tests described in this international standard are summarized in Table 5, with reference to the clause where details of the test are given BS EN 60751:2008 60751  IEC:2008 – 20 – Table – Table of tests described in this standard Routine production tests Resistance tolerance Type tests Resistors Thermometers Resistors Thermometers 6.2.1 6.3.4 6.4.1 6.3.4 Insulation resistance at ambient temperature 6.3.1 6.3.1 Sheath integrity test 6.3.2 6.3.2 Dimensional test 6.3.3 6.3.3 Stability at upper temperature limit 6.4.2 Thermoelectric effect Additional type tests 6.5.3 6.5.4 Self-heating 6.4.3 6.5.7 Insulation resistance at elevated temperatures 6.5.1 Thermal response time 6.5.2 Effect of temperature cycling 6.5.5 Hysteresis 6.5.6 Minimum immersion depth 6.5.8 Capacitance 6.6.1 Inductance 6.6.2 Dielectric strength 6.6.3 Vibration test 6.6.4 Drop test 6.6.5 7.1 Information to be made available by the manufacturer For resistors only Leads of resistors: • length of the leads; • linear resistance in Ω/mm; • temperature coefficient of resistance; • material 7.2 For resistors and/or thermometers • results of all specified type tests; • temperature sensitive length and position of resistor; • ohmic resistance of available for 2-wire equal to or greater respective tolerance Thermometer identification and marking internal connection wires and their temperature coefficient shall be configurations, where the resistance of internal connection wires is than the tolerance value at the maximum rated temperature in the class Each thermometer shall be marked or labelled so that the user may determine either directly or indirectly the number of resistors, nominal resistance, tolerance class, connecting wire configuration and temperature limits BS EN 60751:2008 60751  IEC:2008 – 21 – Example: × Pt 100 / A / / –150 / +500 meaning: • one resistor; • • nominal resistance: R = 100 Ω; tolerance class A (range of validity: –100 °C to 450 °C); • four-wire connection; • lower temperature limit of the thermometer: –150 °C; • upper temperature limit of the thermometer: +500 °C _ This page deliberately left blank This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards Institution (BSI) BSI is the national body 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