BS英国标准BS EN 502712001 Electrical apparatus for the detection and measurement of combustible

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1、BRITISH STANDARD BS EN50271:2002Electrical apparatus for the detection and measurement of combustible gases,toxic gases or oxygen Requirements and tests for apparatus using software and/or digital technologiesThe European Standard EN 50271:2001 has the status of aBritish StandardICS 29.260.20; 71.04

2、0.40NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS EN 50271:2002National forewordThis British Standard is the official English language version ofEN 50271:2001.The UK participation in its preparation was entrusted by Technical Committee GEL/31, Electrical apparatus for expl

3、osive atmospheres, to Subcommittee GEL/31/19, Gas detectors, which has the responsibility to:aid enquirers to understand the text;present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed;monitor related internation

4、al and European developments and promulgate them in the UK.A list of organizations represented on this subcommittee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in th

5、e BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue.A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are res

6、ponsible for their correct application.Compliance with a British Standard does not of itself confer immunity from legal obligations.This British Standard, having been prepared under the direction of the Electrotechnical Sector Policy and Strategy Committee, was published under the authority of the S

7、tandards Policy and Strategy Committee on4 February 2002 BSI 4 February 2002ISBN 0 580 38999 5Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page,pages 2 to 9 and a back cover.The BSI copyright date displayed in this document indicates when the document wa

8、s last issued.Amd. No.DateCommentsAmendments issued since publicationEUROPEAN STANDARDEN 50271NORME EUROPENNEEUROPISCHE NORMNovember 2001ICS 13.320English versionElectrical apparatus for the detection and measurement of combustible gases, toxic gases or oxygen -Requirements and tests for apparatus u

9、sing software and/or digital technologiesAppareils lectriques de dtection et de mesure des gaz combustibles, des gaz toxiques ou de loxygne -Exigences et essais pour les appareils utilisant un logiciel et/ou des technologies numriquesElektrische Gerte fr die Detektion und Messung von brennbaren Gase

10、n, giftigen Gasen oder Sauerstoff -Anforderungen und Prfungen fr Warngerte, die Software und/oder Digitaltechnik nutzenThis European Standard was approved by CENELEC on 2001-05-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving

11、 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 versi

12、ons (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 A

13、ustria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.CENELECEuropean Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrote

14、chnique Europisches Komitee fr Elektrotechnische NormungCentral Secretariat: rue de Stassart 35, B - 1050 Brussels 2001 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.Ref. No. EN 50271:2001 E- 9 -EN 50271:2001ForewordThis European Standard wa

15、s prepared by SC 31-9, Electrical apparatus for the detection and measurement of combustible gases to be used in industrial and commercial potentially explosive atmospheres, of Technical Committee CENELEC TC 31, Electrical apparatus for explosive atmospheres.The text of the draft was submitted to th

16、e formal vote and was approved by CENELEC as EN 50271 on 2001-05-01.The following dates were fixed:-latest date by which the EN has to be implemented at national level by publication of an identicalnational standard or by endorsement(dop)2002-06-01-latest date by which the national standards conflic

17、tingwith the EN have to be withdrawn (dow)2004-04-01Contents1Scope.42Normative references .43Definitions .54Design principles .54.1General design requirements . 54.1.1Analogue/digital interface. 64.1.2 Numerical errors .64.1.3Measuring operation . 64.1.4 Special state indication .64.1.5 Digital indi

18、cation .64.1.6Digital reading (not applicable to alarm only apparatus) .64.2 Software.64.3 Hardware .74.4 Data transmission .74.5 Test routines .75Test of the digital unit .85.1Verification of functional concept. 85.2 Performance test.81 ScopeThis European Standard specifies requirements and tests f

19、or electrical apparatus for the detection and measurement of combustible gases, toxic1 gases or oxygen using software and/or digital technologies. It is applicable to fixed, transportable and portable apparatus intended for use in domestic premises or in industrial applications where safety integrit

20、y levels 1 or 2 of IEC 61508 or safety categories 1 or2 of EN 954-1 are required.In industrial applications this standard is also applicable to apparatus which are intended for use in hazardous areas which may contain explosive or potentially explosive atmospheres.This European standard supplements

21、the requirements of the European Standards for the detection and measurement of combustible gases and vapours (e.g. EN 61779-1 to EN 61779-5, EN 50194), toxic gases (e.g EN 45544, EN 50291) or oxygen (e.g. EN 50104).2 Normative referencesThis European Standard incorporates by dated or undated refere

22、nce, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references , subsequent amendments to or revisions ofany of these publications apply to this European Standard only when incorporat

23、ed in it by amendment or revision. For undated references the latest of the publication referred to applies.EN 954-1Safety of machinery.Safety related parts of control systems - Part 1: General principles for designEN 45544-1Workplace atmospheres - Electrical apparatus used for the direct detection

24、and direct concentration measurement of toxic gases and vapoursPart 1: General requirements and test methodsEN 45544-2Part 2: Performance requirements for apparatus used for measuring concentrations in the region of limit valuesEN 45544-3Part 3: Performance requirements for appartus used for measuri

25、ng concentrations well above limit valuesEN 45544-4Part 4: Guide for selection, intallation, use and maintenanceEN 50104Electrical apparatus for the detection and measurement of oxygen Performance requirements and test methodsEN 50194Electrical apparatus for the detection of combustible gases in dom

26、estic premises Test methods and performance requirementsEN 50291Electrical apparatus for the detection of carbon monoxide in domestic premises Test methods and performance requirementsEN 61779-1Electrical apparatus for the detection and measurement of flammable gasesPart 1: General requirements and

27、test methods1For the purposes of this standard the word toxic should be taken to include very toxic, toxic, harmful, corrosive, irritating,carcinogenic, mutagenic and toxic to reproduction.EN 61779-2Part 2: Performance requirements for group I apparatus indicating a volume fraction up to 5 % methane

28、 in airEN 61779-3Part 3: Performance requirements for group I apparatus indicating a volume fraction up to 100 % methane in airEN 61779-4Part 4: Performance requirements for group II apparatus indicating a volume fraction up to 100 % lower explosive limitEN 61779-5Part 5: Performance requirements fo

29、r group II apparatus indicating a volume fraction up to 100 % gasIEC 61508-1Functional safety of electrical/electronic/programmable electronic safety- related systems - Part 1 : General requirementsIEC 61508-3Functional safety of electrical/electronic/programmable electronic safety- related systems

30、- Part 3 : Software requirements3 DefinitionsFor the purposes of this European Standard, the definitions given in EN 61779-1 apply together with the following definitions:3.1digital unitpart of an electrical apparatus in which data is processed digitally. Analogue-digital(A/D)-converters and digital

31、-analogue(D/A)-converters as interfaces to analogue units of the apparatus belong to the digital unit3.2special stateall states of the apparatus other than those in which monitoring of gas concentration take place, for example warm-up, calibration mode or fault condition3.3 softwareintellectual crea

32、tion comprising the programs, procedures, rules and associated documentationpertaining to the operation of the digital unit3.4safety-related softwaresoftware that is used to implement safety functions3.5 parameterssettings by the manufacturer or user which effect the operation of the software, e.g.

33、changing of alarmthresholds or measurement units. Parameter options are included in the software during design of the apparatus. Changes of parameter settings are not modifications of the software4 Design principles4.1 General design requirementsIn general the design of digital units has to follow g

34、ood design practice. Requirements are listed in the following clauses.4.1.1 Analogue/digital interfaceThe relationship between corresponding analogue and digital values shall be unambiguous. The output range shall be capable of coping with the full range of input values within the instrument specifi

35、cation. A clear indication shall result if the conversion range has been exceeded. A/D- and D/A- converter quantisation steps shall be chosen so that the requirements in 4.1.2 for the accuracy of data representation will be fulfilled. The design shall take into account the maximum possible A/D- andD

36、/A-converter errors.4.1.2 Numerical errorsThe resolution of data formats and precision to which values are computed shall be chosen so that any errors arising from the digital processing shall not be greater than the smallest deviation of indication required by the applicable European Standard. Duri

37、ng data processing the digital unit shall control automatically the allowed input, output and internal data range and handle range violations. Estimation of deviations of measured values arising from quantisation, rounding and calculation errors shall take into account worst case conditions.4.1.3 Me

38、asuring operationDuring measuring operation, the maximum overall time of four successive updates of the output value shall not exceed the response time t90 , as required by the applicable European Standard, or time to alarm for alarm only apparatus4.1.4 Special state indicationIf a special state is

39、entered by an apparatus this shall be indicated by a signal. The special state shall be also indicated on outputs provided for remote transmission of measuring values.4.1.5 Digital indicationIf data for several indications are generated simultaneously by an apparatus it shall be possible to identify

40、 the indications. A combined signal shall be generated if all indications cannot be activated. In this case the indication with the highest safety priority at a given time shall be displayed or activated simultaneously. (Preferences of safety importance of indications shall be set suitably for each

41、apparatus and documented in the instruction manual). It shall be possible to interrogate the indications that are not currently shown or activated.If release of an indication encloses the automatic release of a second subsidiary indication (e. g. exceeding the 2nd limiting value includes exceeding t

42、he 1st limiting value) it is sufficient to show the indication of higher priority. After cancelling the higher order indication the subsidiary indication shall remain if the reason for its activation still exists.4.1.6 Digital reading (not applicable to alarm only apparatus)For indicated measured va

43、lues the displayed unit of measurement and any related sign shall be unambiguous. Any under-range or over-range measurements shall be clearly indicated.4.2 SoftwareSoftware components shall comply with IEC 61508-3 safety integrity levels 1 and 2. In particular :a)It shall be possible for the user to

44、 identify the installed software version, for example by marking on the installed memory component, in (if accessible) or on the apparatus or by showing it on the display during power up or on user command.b)It shall not be possible for the user to modify the software function.c)Parameter settings s

45、hall be checked for validity. Invalid inputs shall be rejected. An access barrier shall be provided against parameter changing by unauthorised persons, e. g. it may be integrated by an authorisation code in the software or may be realised by a mechanical lock. Parameter settings shall be preserved a

46、fter apparatus switch-off and while passing a special state. All user changeable parameters and their valid ranges shall be listed in the manual.d)Software shall have a structured and modular design to facilitate testing and maintenance.Program modules shall have a clearly defined interface to other

47、 modules.e)Software documentation shall be included in the technical file of the product. It shall include: the apparatus to which the software belongs; unambiguous identification of program version; type and version of software tools used; source code of safety-related software modules; functional

48、description; software structure (e. g. flow chart, Nassi-Schneidermann diagram); software validation protocols; any software modification provided with the date of change and new identification data.NOTE The documentation is only for the use of the test laboratory. All information is confidential an

49、d is the property of the manufacturer.f) When third party approval includes safety related software, modifications of software functions by the manufacturer shall be notified to the third party. Modifications shall be fully documented and explained. Further testing may be necessary depending on the

50、complexity of the modification.4.3 HardwareComponents shall only be used within their specifications or they shall be verified by individual testing. For interconnection between components, cabling and other interface specifications shall be adhered to.It shall be impossible to change the program co

51、de under any operating conditions. Upgrades shall only be possible under the control of the manufacturer.To store parameters and variables, which should be permanent even after switch-off or during a special state, storage parts shall be used in which the data content remains permanent when the supp

52、ly voltage is removed. Where a battery is used for this purpose, the instruction manual shall indicate the life time of the data storage.4.4 Data transmissionDigital data transmission between spatially separated components of apparatus shall be reliable. Delays resulting from transmission errors sha

53、ll not extend the response time t90 or time to alarm for alarm only apparatus by more than 1/3. If not the apparatus shall pass over to a defined special state. The defined special state shall be documented in the instruction manual.4.5 Test routinesComputerised digital units shall incorporate test

54、routines. On failure detection, the apparatus shall pass over to a defined special state. The defined special state shall be documented in the instruction manual.The following minimum tests shall be performed by the apparatus:a) power supply of digital units shall be monitored within time intervals

55、of maximum ten times response time t90 or time to alarm for alarm only apparatus;b) all available visible and audible output functions shall be tested. The test shall be carried out automatically after starting operation or on user request. The result may need to be verified by the user;c) monitorin

56、g equipment with its own time base (e. g. watchdog) shall work independently and separately from the parts of the digital unit which perform the data processing. If a failure is detected by the monitoring equipment the apparatus shall enter into a special state;d) program and parameter memory shall be monitored by procedures which allow the detection of a single bit error;e) volatile memory shall be monitored by procedures that test the readability and writeability of the memory cells.The tests except for test b) shall