EN 50271:2001

SLOVENSKI STANDARD
01-september-2002
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Electrical apparatus for the detection and measurement of combustible gases, toxic
gases or oxygen - Requirements and tests for apparatus using software and/or digital
technologies
Elektrische Geräte für die Detektion und Messung von brennbaren Gasen, giftigen
Gasen oder Sauerstoff - Anforderungen und Prüfungen für Warngeräte, die Software
und/oder Digitaltechnik nutzen
Appareils électriques de détection et de mesure des gaz combustibles, des gaz toxiques
ou de l'oxygène - Exigences et essais pour les appareils utilisant un logiciel et/ou des
technologies numériques
Ta slovenski standard je istoveten z: EN 50271:2001
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50271
NORME EUROPÉENNE
EUROPÄISCHE NORM November 2001
ICS 13.320
English version
Electrical apparatus for the detection and measurement of combustible
gases, toxic gases or oxygen -
Requirements and tests for apparatus using software
and/or digital technologies
Appareils électriques de détection et de Elektrische Geräte für die Detektion und
mesure des gaz combustibles, des gaz Messung von brennbaren Gasen, giftigen
toxiques ou de l'oxygène - Gasen oder Sauerstoff -
Exigences et essais pour les appareils Anforderungen und Prüfungen für
utilisant un logiciel et/ou des technologies Warngeräte, die Software und/oder
numériques Digitaltechnik nutzen
This 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 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, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands,
Norway, Portugal, Spain, Sweden, Switzerland and 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
© 2001 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50271:2001 E
Foreword
This European Standard was 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 the 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 identical
national standard or by endorsement (dop) 2002-06-01
- latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2004-04-01
__________
- 3 - EN 50271:2001
Contents
1 Scope.4
2 Normative references.4
3 Definitions .5
4 Design principles.5
4.1 General design requirements .5
4.1.1 Analogue/digital interface.6
4.1.2 Numerical errors .6
4.1.3 Measuring operation .6
4.1.4 Special state indication .6
4.1.5 Digital indication .6
4.1.6 Digital reading (not applicable to alarm only apparatus) .6
4.2 Software.6
4.3 Hardware .7
4.4 Data transmission .7
4.5 Test routines .7
5 Test of the digital unit .8
5.1 Verification of functional concept.8
5.2 Performance test.8

1 Scope
This European Standard specifies requirements and tests for electrical apparatus for the detection
and measurement of combustible gases, toxic 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 integrity levels 1 or 2 of IEC 61508 or safety categories 1 or
2 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 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 references
This European Standard incorporates by dated or undated reference, 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 of
any of these publications apply to this European Standard only when incorporated in it by amendment
or revision. For undated references the latest of the publication referred to applies.
EN 954-1 Safety of machinery.Safety related parts of control systems - Part 1:
General principles for design
EN 45544-1 Workplace atmospheres - Electrical apparatus used for the direct
detection and direct concentration measurement of toxic gases and
vapours
Part 1: General requirements and test methods
EN 45544-2 Part 2: Performance requirements for apparatus used for measuring
concentrations in the region of limit values
EN 45544-3 Part 3: Performance requirements for appartus used for measuring
concentrations well above limit values
EN 45544-4 Part 4: Guide for selection, intallation, use and maintenance
EN 50104 Electrical apparatus for the detection and measurement of oxygen –
Performance requirements and test methods
EN 50194 Electrical apparatus for the detection of combustible gases in domestic
premises – Test methods and performance requirements
EN 50291 Electrical apparatus for the detection of carbon monoxide in domestic
premises – Test methods and performance requirements
EN 61779-1 Electrical apparatus for the detection and measurement of flammable
gases
Part 1: General requirements and test methods

For 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´.

- 5 - EN 50271:2001
EN 61779-2 Part 2: Performance requirements for group I apparatus indicating a
volume fraction up to 5 % methane in air
EN 61779-3 Part 3: Performance requirements for group I apparatus indicating a
volume fraction up to 100 % methane in air
EN 61779-4 Part 4: Performance requirements for group II apparatus indicating a
volume fraction up to 100 % lower explosive limit
EN 61779-5 Part 5: Performance requirements for group II apparatus indicating a
volume fraction up to 100 % gas
IEC 61508-1 Functional safety of electrical/electronic/programmable electronic safety-
related systems - Part 1 : General requirements
IEC 61508-3 Functional safety of electrical/electronic/programmable electronic safety-
related systems - Part 3 : Software requirements
3 Definitions
For the purposes of this European Standard, the definitions given in EN 61779-1 apply together with
the following definitions:
3.1
digital unit
part of an electrical apparatus in which data is processed digitally. Analogue-digital(A/D)-converters
and digital-analogue(D/A)-converters as interfaces to analogue units of the apparatus belong to the
digital unit
3.2
special state
all states of the apparatus other than those in which monitoring of gas concentration take place, for
example warm-up, calibration mode or fault condition
3.3
software
intellectual creation comprising the programs, procedures, rules and associated documentation
pertaining to the operation of the digital unit
3.4
safety-related software
software that is used to implement safety functions
3.5
parameters
settings by the manufacturer or user which effect the opera
...