1、BRITISH STANDARD AEROSPACE SERIESBS EN 3475-705:2005Cables, electrical, aircraft use Test methods Part 705: Contrast measurementThe European Standard EN 3475-705:2005 has the status of a British StandardICS 49.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g
2、44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Licensed Copy: Wang Bin, na, Mon May 08 03:39:51 BST 2006, Uncontrolled Copy, (c) BSIBS EN 3475-705:2005This British Standard was published under the authority of the Standards Policy and
3、 Strategy Committee on 10 February 2006 BSI 10 February 2006ISBN 0 580 47796 7National forewordThis British Standard is the official English language version of EN 3475-705:2005. It supersedes BS EN 3475-705:2002 which is withdrawn.The UK participation in its preparation was entrusted by Technical C
4、ommittee ACE/6, Aerospace avionic electrical and fibre optic technology, to Subcommittee ACE/6/-/2, Aerospace Cables, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary.Cross-referencesThe British Standards which impl
5、ement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication doe
6、s not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/Europea
7、n committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to
8、10, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsLicensed Copy: Wang Bin, na, Mon May 08 03:39:51 BST 2006, Uncontrolled Copy, (c) BSIEUROPEAN STANDARDNOR
9、ME EUROPENNEEUROPISCHE NORMEN 3475-705October 2005ICS 49.060 Supersedes EN 3475-705:2002 English VersionAerospace series - Cables, electrical, aircraft use - Testmethods - Part 705: Contrast measurementSrie arospatiale - Cbles lectriques usagearonautique - Mthodes dessais - Partie 705 : Mesure decon
10、trasteLuft- und Raumfahrt - Elektrische Leitungen frLuftfahrtverwendung - Prfverfahren - Teil 705:KontrastmessungThis European Standard was approved by CEN on 12 September 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this Eu
11、ropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English,
12、 French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Rep
13、ublic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATI
14、ONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 3475-705:2005: ELicensed Copy: Wang Bin, na, Mon May 08 03:39:51 BST 2006, Uncontrolled Copy,
15、 (c) BSI2 Contents Page Foreword 3 Introduction4 1 Scope .4 2 Normative references .4 3 Terms and definitions.5 4 Preparation of samples 5 5 Apparatus, measurement and process .6 5.1 Apparatus 6 5.2 Measurement.7 5.3 Process8 6 Requirements 10 EN 3475-705:2005Licensed Copy: Wang Bin, na, Mon May 08
16、03:39:51 BST 2006, Uncontrolled Copy, (c) BSI3 Foreword This European Standard (EN 3475-705:2005) has been prepared by the European Association of Aerospace Manufacturers - Standardization (AECMA-STAN). After enquiries and votes carried out in accordance with the rules of this Association, this Stan
17、dard has received the approval of the National Associations and the Official Services of the member countries of AECMA, prior to its presentation to CEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the late
18、st by April 2006, and conflicting national standards shall be withdrawn at the latest by April 2006. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such
19、patent rights. This European Standard supersedes EN 3475-705:2002. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, Fr
20、ance, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 3475-705:2005Licensed Copy: Wang Bin, na, Mon May 08 03:39:51 BST 2006, Uncontrolled Copy, (
21、c) BSI4 Introduction It is a requirement within the aerospace industry that all wires and cables within an aircraft electrical system are identified with a circuit identification code at regular intervals down the length of the wire. Various marking methods are used for marking these identification
22、codes on to the surface of electrical wires or cables including ink based and laser based processes. The legibility of the markings is dependent upon the process used and the insulation medium. Minimum standards of contrast are required to facilitate reading back of the identity codes. 1 Scope This
23、standard specifies the process to be applied for measuring the contrast of wire and cable identification markings against the background of the unmarked wire insulation. It has been developed primarily to define a reproducible process of contrast value determination for use both to determine the int
24、rinsic laser markability of wires at the time of manufacture or later, and to enable electrical wiring systems manufacturers to ensure that the whole process of wire marking is carried out to the required standard. 2 Normative references The following referenced documents are indispensable for the a
25、pplication 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. ISO 7724-1, Paints and varnishes Colorimetry Part 1: Principles. EN 3475-706, Aerospace series Cables, electric
26、al, aircraft use Test methods Part 706: Laser markability. IEC 15-2, Colorimetry. TR 4543, UV laser wire marking systems for aircraft wire and cable identification.1)1) In preparation at the date of publication of this standard. EN 3475-705:2005Licensed Copy: Wang Bin, na, Mon May 08 03:39:51 BST 20
27、06, Uncontrolled Copy, (c) BSI5 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 contrast the ratio of the difference in luminance between the marked and unmarked areas of the insulation divided by the luminance of the unmarked insulation 3.2
28、luminance the quantitative measurement of the visible light reflected from a surface, in this case the wire or cable insulation 3.3 laser laser is an acronym for Light Amplification by the Stimulated Emission of Radiation. Lasers are a source of intense monochromatic light in the ultraviolet, visibl
29、e or infrared region of the spectrum. 3.4 ultraviolet (abbreviation UV) electromagnetic radiation in a wavelength range from approximately 200 nm to 400 nm 3.5 UV laser a laser that produces a beam of UV radiation 3.6 fluence the energy density, measured in J cm-2(Joules per square cm) of a single p
30、ulse of the laser beam, which, for the purposes of this document, is taken at the surface of the wire insulation or cable jacket 3.7 wavelength wavelength () is measured in nanometres, nm. 1 nm = 10-9m. = c/f where c is the velocity of light and f is the frequency 4 Preparation of samples The wire o
31、r cable samples shall be identified in accordance with the applicable manufacturing instructions for the marking equipment. Where samples are to be UV laser marked this shall be done using the fluence specified in TR 4543 or the relevant wire or aircraft manufacturers process specification if differ
32、ent. When determining the laser markability of wires, this shall be in accordance with EN 3475-706. Take a sample of the wire for marking. Before marking the wire ensure that the wire surface is clean and dry and free from dust and dirt; if necessary wipe it clean using propan-2-ol (isopropyl alcoho
33、l). The surfaces of the samples shall be clean and without damage. The identification markings to be measured shall be even in colour and characters shall have well defined edges. Before starting measurements clean the surfaces with a soft, lint-free cloth, if required, to avoid distortion of test r
34、esults by a roughened surface or “deposits”. EN 3475-705:2005Licensed Copy: Wang Bin, na, Mon May 08 03:39:51 BST 2006, Uncontrolled Copy, (c) BSI6 5 Apparatus, measurement and process 5.1 Apparatus 5.1.1 Components of the measuring device The measuring device shall comprise, at a minimum, a photome
35、ter, an illumination system and a purpose designed sample holder suitable for wire and cable. The whole system shall be designed to ensure that test results are not falsified by external influences. The photometer shall be designed to be stable and free from vibrations and to exclude the influences
36、of external light and reflections from scattered light. 5.1.2 Equipment colour The device for holding samples and any accessories and the equipment in the vicinity of the measurement area shall be matt black in colour to absorb scattered light. 5.1.3 Photometer The luminance shall be determined with
37、 a calibrated electrical photometer, which shall incorporate a photopic filter to simulate the response of the human eye. The manufacturers instructions concerning the photometer working range and operating instructions shall be observed. The measurement sensitivity of the photometer shall be in con
38、formity with IEC publication 15-2. 5.1.4 Illumination and viewing system The illumination system shall consist of two light sources of equal intensity (see Figure 1). The two sources may be two separate lamps or, preferably, two fibre light guides fed from a single lamp. The light from the sources s
39、hall overlap to illuminate a central spot on the sample at an angle of 45oto the surface. The light cones shall illuminate the wire sample longitudinally along its length and in a manner to avoid the formation of shadows. The photometer must be installed to view the sample along the normal to the su
40、rface, i.e. at 90o, and above the principal focus at a distance that depends on the objectives focal distance. It shall be adjusted during calibration and after every change of objective. If two separate lamps are used they shall be of identical power consumption and shall always be exchanged in pai
41、rs. The radiating light energy and colour temperature of the lamps shall be compatible with the working range of the photometer, according to the manufacturers instructions. The spectral distribution of the light shall be close to artificial light specifications according to light standard A, ISO 77
42、24-1. Only gas filled lamps with tungsten filaments shall be used. The colour temperature shall be (3 000 500) K. The voltage supply for the lamps shall be insensitive to line fluctuations. A stabilised d.c. power unit shall be used. EN 3475-705:2005Licensed Copy: Wang Bin, na, Mon May 08 03:39:51 B
43、ST 2006, Uncontrolled Copy, (c) BSI7 Key 1 Photometer 2 Source of light 3 Marked cable Figure 1 Lighting equipment 5.2 Measurement 5.2.1 Equipment design and measurement methodology To determine the contrast, measurements must be taken of the luminance from both marked and unmarked areas of the insu
44、lation. Depending upon the contrast measurement equipment design, the photometer may be used either to take a series of individual point measurements sequentially or it may determine the contrast instantaneously by the simultaneous measurement of the luminance of all the sample points of an area of
45、the sample. If a point measurement system is used, sufficient points shall be sampled on both the marked and unmarked portion of the wire to ensure that a good average value of the reflectance of each is obtained. 5.2.2 Measurement spot size The maximum admissible diameter of the photometer measurem
46、ent spot shall be not in excess of 75 % of the character stroke width. This is particularly important if using a point measurement system where spot sizes are typically relatively large. 5.2.3 Measurement area The contrast shall be measured over a finite area to include a significant portion of the
47、marked and the unmarked surface of the wire. EN 3475-705:2005Licensed Copy: Wang Bin, na, Mon May 08 03:39:51 BST 2006, Uncontrolled Copy, (c) BSI8 It is important that spot measurements should not be made immediately adjacent to the edge of a character, either on the mark or the unmarked insulation
48、, to avoid scattered light from the adjacent area from interfering with the measurement. Area measurement systems should discriminate against such scattered light by suitable means. 5.2.4 Calibration The photometer shall be calibrated by use of a reference sample, e.g. ceramic tiles, of known reflec
49、tance, certified and traceable to National Standards. The frequency of calibration shall be in accordance with the equipment manufacturers guidelines. 5.2.5 Measurement tolerance The measuring tolerance of the photometer shall be not more than 2 %. 5.3 Process 5.3.1 Precautionary measures There may be a danger from some illumination systems that they may cause the samples to heat up significantly. If this is the case then measurements should be taken without delay and the sample removed from the test area after the measurements have been t
