CERN EQUIPMENT IDENTIFICATION

Transcription

1 CERN CH-1211 Geneva 23 Switzerland the Large Hadron Collider project LHC Project Document No. CERN Div./Group or Supplier/Contractor Document No. - EDMS Document No Date: Quality Assurance Definition CERN EQUIPMENT IDENTIFICATION Abstract This document presents the part identification scheme used for all equipment placed under the responsibility of CERN and installed on the CERN site or elsewhere. The part identifier defined by the scheme is essential to link equipment information stored and managed with the CERN EDMS (Engineering Data Management System), or with other data management system. Equipment labelled according to the CERN equipment identification scheme is guaranteed to be uniquely and unambiguously identified within the entire CERN domain of responsibility. Therefore it enables the traceability of equipment, one of the requirements of CERN's quality and safety procedures. Prepared by : David Widegren TS/CSE david.widegren@cern.ch Marcel Mottier TS/CSE Marcel.Mottier@cern.ch Checked by : Elena Manola-Poggioli LHC Latchezar Betev ALICE Kathy Pommes ATLAS Frank Glege CMS Rolf Lindner LHCb TOTEM Ronny Billen AB Thomas Pettersson TS Approved by : Paul Proudlock LHC Lars Leistam ALICE Marzio Nessi ATLAS Austin Ball CMS Werner Witzeling LHCb Marco Oriunno TOTEM Jean-Pierre Delahaye AB Paolo Ciriani TS

2 Page 2 of 12 History of Changes Rev. No. Date Pages Description of Changes First Draft by D.Widegren. Checked and reviewed by T.Pettersson. Code prefix for ATLAS extended and coding scheme changed for Totem draft Code prefix for LHC changed and coding scheme section shortened. References added. Approved by LHC QA WG Extension of scope and addition of the CR prefix. Extension of the scope, also including existing project/experiments/machines. Extension of the scope to cover all CERN equipment. Addition of procedure for approval of the document and its future modifications. Extensions of the range of prefixes attributed to the four LHC detectors. Removal of references to INB regulations. Reference to ST Division replaced by TS Department. Released. Released version includes a reference to ALICE coding scheme. References to EST Division replaced by TS Department. 2.2 draft Addition of prefix for the PS-Complex. Released. Released version contains some minor language corrections and a reference to the group EST/ISS has been changed to TS/CSE.

3 Page 3 of 12 Table of Contents 1. PURPOSE POLICY SCOPE EQUIPMENT COVERED BY THE SCHEME EQUIPMENT NOT COVERED BY THE SCHEME EQUIPMENT IDENTIFICATION SCHEME PREFIX COMPONENT CODE - RECOMMENDATIONS PROCEDURES RECOMMENDATION FOR LABELLING EQUIPMENT BARCODE STANDARDS BARCODE STICKERS REFERENCES...8 ANNEX 1: APPROVED CERN PART ID PREFIXES...9 ANNEX 2: PREFIXES UNDER REVIEW AND NOT APPROVED...9 ANNEX 3: BARCODES...10

4 Page 4 of PURPOSE 2. POLICY CERN regulations, as well as good quality assurance practice, require that equipment 1 be uniquely identified so that it can be traced throughout its entire lifecycle. To achieve this objective a general solution for attributing part identifier is necessary. Part identifiers are an essential element needed to link the physical items to the corresponding data in the CERN EDMS or other engineering databases. They may also be used as links between equipment related information stored in different administrative, technical and physics information systems at CERN or elsewhere. Equipment labelled according to the scheme presented in this document is guaranteed to be uniquely and unambiguously identified within the entire CERN domain of responsibility. The document also gives examples of how part identifiers can be represented by barcodes, in most cases the quickest and least expensive way of physically associating the identifier with the piece of equipment itself. CERN regulations, and the trend towards a unique, or at least a very limited number of equipment management systems, require that part numbering schemes are coordinated on a CERN wide basis including the physics collaborations installing and operating experiments at CERN. The CERN equipment identification scheme aims at: Ensuring that part identifiers 2 are unique and unambiguous. Ensuring that new installations 3 can fit in the CERN scheme while retaining the ability to use installation-specific schemes. Ensuring that equipment already installed can fit in the CERN scheme. Providing, within any part identifier, a simple way to distinguish between the different installation-specific component coding schemes. To ensure that these aims are achieved the CERN part identifier is made of two parts: A prefix, managed on a CERN wide basis including the physics collaborations. An installation-specific component code defined under the sole responsibility of the team in charge of the specific installation. The list of prefixes is approved by authorised persons representing all major installations. Any modification, addition or deletion from the list of prefixes will have to be reviewed and approved by the same procedure as the original list. 1 Equipment stands for physical individual components and assemblies of components 2 The part identifier is used to identify parts or sub-assemblies or assemblies 3 Installation stands for a large detector or a group of small detetors; a large accelerator or a group of smaller machines; a large workshop. A prefix may also be attributed to a large set of components not related to a specific installation.

5 Page 5 of SCOPE 3.1 EQUIPMENT COVERED BY THE SCHEME The part identifier scheme described in this document is applicable to: All new equipment placed under the responsibility of CERN. All equipment that is managed with the CERN EDMS system. It is applicable to all equipment defined above irrespectively of the site of installation of the equipment. The CERN equipment identifier scheme is recommended, but not compulsory, for all other equipment. 3.2 EQUIPMENT NOT COVERED BY THE SCHEME The part identifier scheme described in this document is not applicable to the functional position of equipment, nor is it applicable to cables installed under the responsibility of the Electrical Group of the TS Department. 4. EQUIPMENT IDENTIFICATION SCHEME Equipment, i.e. parts, sub-assemblies and assemblies are identified by a part identifier made of two elements: A prefix, made up of 2 alphanumeric characters. A component code, of variable length, made up of alphanumeric characters. Prefix defining the component coding scheme used. Component code X X X X X X X X X X X X X X A B Figure 1 - The part identifier structure 4.1 PREFIX The scheme provides for 676 alphabetical prefixes, 100 numerical prefixes, and 520 alphanumeric prefixes. Numerical prefixes are reserved in priority for equipment of small dimensions where the size of bar code labels is an important consideration. The complete list of approved prefixes is given in annex 1 of this document. This annex is available as a separate file named CERN-PART-ID-PREFIX of this document (EDMS No ). Annex 1 also includes the list of new prefixes under consideration but not yet approved.

6 4.2 COMPONENT CODE - RECOMMENDATIONS LHC Project Document No. Page 6 of 12 The length of the component code can vary from the CERN EDMS point of view. 4 The maximum length should however not exceed 22 characters (i.e. 24 in total for the complete part identifier) since this is the upper for limit for identifiers in the ISO standard and in some applications in use at CERN. It is essential to remember that the identifier cannot be changed after the registration procedure. This means that if significant information about the part is put in the identifier, this should be of such kind that it does not change over time. Descriptive data such as position and other characteristics that might change should be stored as attributes of the part in the appropriate database. On the other hand information such as production site may well be included in the code. To do so is an advantage since it allows the generation of part identifiers and barcodes in parallel on several locations while ensuring that they are unique. The part identifier must be unique and when part identifiers are created by the CERN EDMS the system will check this uniqueness. However, there is no check of what information is put into the identifier. It is therefore totally up to the person in charge of each installation to ensure that a reliable procedure is implemented to produce component codes so that only appropriate information is included in the part identifier PROCEDURES In practice the approval of the prefixes is carried out by approving the present document. This guarantees that all interested parties are made aware of the scheme, and it ensures consistency in the attribution of prefixes over time. It is the responsibility of the persons approving the prefixes to inform all interested parties in their domain of responsibility. Any modification, addition or deletion from the list of prefixes will have to be approved in the same way as the original list. Requests for new prefixes, for modification or deletion of prefixes have to be submitted by the person or authority representing the installation concerned to the organisational unit in charge of quality assurance for LHC 6. After reviewing the request to verify that it is legitimate and coherent with the overall concept, the request will be circulated for comments and approval by the authorised representatives of the major installations. In case of conflicts, the request will be submitted to the appropriate CERN technical coordination committees to be resolved. 6. RECOMMENDATION FOR LABELLING EQUIPMENT The idea is, as explained earlier, to label each part with an identifier to enable traceability of individual parts. There are several ways of labelling items of which barcoding is perhaps the most interesting. 4 A recommended length for the full code is 14-characters (2+12) since this gives a certain freedom to include some intelligence and structureing of it and still be able have a fairly large sequential number at disposal. The 14 character code is also supported by most of the commonly used barcode standards. 5 The documents describing strategies and detailed identification schemes defined for each installation are listed in the references of this document. 6 Currently this is the reponsibility of the TS/CSE group

7 Page 7 of BARCODE STANDARDS To start with, there are several different standards of one-dimensional barcodes which can be divided into two main groups; those that allow alphanumerical values and those that only allow numerical values. Among all the standards the following two are the most commonly used in industry applications and the most widely recommended from each group: Interleaved 2 of 5, Numeric-only barcode, compact numeric code, widely used in industry, air cargo and other applications. Code 128, Alphanumeric barcode (the full ASCII set of 128 characters), excellent density, high reliability; commonly used world-wide. The recommended choice is Code 128 since this offers alphanumerical entries, it is more flexible and it is more reliable since a checksum is already included in the standard. In cases where the actual size of components prevent the use of Code 128 printed labels the Interleaved 2 of 5 code may be used since it is more compact than Code 128. It should however be noted that Code 128 becomes significantly more compact if only digits are used. 7 When using the 2 of 5 Interleaved barcode standard, it is strongly recommended to use fixed length code since a partial scan of a label has a high probability of being decoded as another valid, but shorter code. The number of digits in this code must also be even. Code 128 does not have any of these limitations. As a final remark it should be made very clear that it is actually possible to use both these barcode standards in parallel because almost all modern barcode readers can interpret all major standards. 6.2 BARCODE STICKERS There are technical aspects that must be considered when selecting barcodes: Sufficient printing resolution must be used. The sticker environment (high temperatures, radiation, detergents and so on) may dictate the use of a specific support. It is vital to make sure that the process of printing barcode stickers is fully controlled to avoid printing the same barcode twice by mistake. 7 More detailed information about the barcodes and the procedure to calculate the dimension of a barcode label can be found in annex 3.

8 Page 8 of REFERENCES [1] ATLAS Part Identification, ATC-OQ-QA-2040, J.Callahan, F.Dittus, K.McFarlane [2] LHC Part Identification, LHC-PM-QA-206, M.Mottier [3] CMS ECAL Barcode Strategy, LEMIC Annex 5, J-M. Le Goff [4] LHCb Part Identification, LHCB-C-MN-0003, W. Witzeling [5] CERN multi purpose equipment identification, (in preparation), D. Widegren [6] Naming and Numbering Convention for ALICE detector part identification - Generic Scheme ALICE-INT [7] Conventions for Identifiers and Names of Equipment in the PS-Complex, EDMS Doc , R. Billen

9 Page 9 of 12 ANNEX 1: APPROVED CERN PART ID PREFIXES Prefix Installation Approved by 1X 8 ALICE Lars Leistam 2X 9 ATLAS Marzio Nessi 3X 10 CMS Austin Ball 4X 11 LHCb Werner Witzeling 50 TOTEM (except in CMS) Marco Oriunno CR CERN multi-purpose material Paolo Ciriani HC LHC machine Paul Proudlock PX PS Complex Jean-Pierre Delahaye ZZ Off the shelf items Paolo Ciriani ANNEX 2: PREFIXES UNDER REVIEW AND NOT APPROVED Prefix Installation To be approved by 8 Where X can be a character in the range A to Z or a number in the range 0 to 9. 9 Where X can be a character in the range A to Z or a number in the range 0 to Where X can be a character in the range A to Z or a number in the range 0 to Where X can be a character in the range A to Z or a number in the range 0 to 9.

10 Page 10 of 12 ANNEX 3: BARCODES Interleaved 2 of 5 (CODE 25) 12 Interleaved 2 of 5 (code 25) is a numeric-only barcode widely used in warehouse and industrial applications. The data must consist of an even number of digits. Each data character is composed of 5 elements, either 5 bars or 5 spaces. Of these 5 elements, two are wide and three are narrow. Adjacent characters are interleaved, alternating the spaces from one character with the bars of the other. CODE Code 128 provides excellent density for all-numeric data and good density for alphanumeric data. It is often selected over Code 39 in new applications because of its density and because it offers a much larger selection of characters. The Code 128 standard is maintained by AIM (Automatic Identification Manufacturers). The Code 128 character set includes the digits 0-9, the letters A-Z (upper and lower case), and all standard ASCII symbols and control codes. The codes are divided into three subsets A, B, and C. There are three separate start codes to indicate which subset will be used; in addition, each subset includes control characters to switch to another subset in the middle of a barcode. Subset A includes the standard ASCII symbols, digits, upper case letters, and control codes. Subset B includes standard ASCII symbols, digits, upper and lower case letters. Subset C compresses two numeric digits into each character, providing excellent density. Here is a sample that contains 12 digits; compare its size to the sample at the top of the section that contains 12 assorted characters: Each character is 11 times the width of the narrowest bar; using a minimum bar width of 0.010" each character would be 0.11" wide. Using the 0.010" figure, 20 data characters plus start code, check digit, and stop code would measure 2.55" wide (the stop code is 13 times as wide as a narrow bar). Using Subset C with all-numeric data provides 2:1 compression of the data for a total width of 1.45". Each character consists of 3 bars and 3 spaces, each of which may be 1, 2, or 3 elements wide (1 element = 1/11th of the character width). The bars always use an even number of elements and the spaces use an odd number. This provides the basis for a character-by-character consistency check during scanning. In addition, each Code 128 barcode includes a Modulo 103 checksum. 12 Information from The Barcode Software Center, 13 idem

11 Page 11 of 12 The Checksum Calculating the checksum can be a little tricky. Each Code 128 character has a numeric value from 0 to 102. In Subset A and B, the numeric value of a character is its ASCII code minus 32. For instance, a space (ASCII 32) has a value of 0, the exclamation point (ASCII33) has a value of 1, etc. Subset A permits printing of ASCII control characters, those with ASCII codes between 0 and 31. For these characters add 64 to the ASCII code to obtain the numeric value. For example, the value of NUL (ASCII 0) is 64, SOH (ASCII 1) is 65, STX (ASCII 2) is 66, etc. Subset C prints numeric digits in pairs, and the value of the character for checksum purposes is the numeric value of the pair (00, 01, ). To calculate the checksum, follow these steps: 1. Initialise the checksum variable with the value of the start character (103, 104, or 105 for Subsets A, B, or C, respectively). 2. Initialise a multiplier to Starting at the left end of the barcode data, add the numeric value of each character times the multiplier to the checksum. Increment the multiplier after each character. 4. Divide the result by 103. The remainder is the checksum. 5. Convert the numeric checksum into an ASCII character. The details of converting the numeric checksum to an ASCII character may vary depending on the particular font being used. Special handling may be required in cases where the resulting ASCII character code equals zero or is above 95. Generally speaking, in Subset A if the checksum is between 0 and 63 inclusive, add the checksum and the ASCII code for a space (32) to obtain the character code. If the checksum is 64 or higher, subtract 64 to obtain the character code. In Subset B, add the checksum and the ASCII code for a space (32). In Subset C, the checksum is the ASCII value of the character.

12 Page 12 of 12 How to calculate the barcode dimension? An important issue to think about when choosing barcode standard, is of course what dimension the barcodes will get in the end. The simple formulas show below can help to check this in advance. 14 Interleaved 2 of 5: L = X [C/2 (4N + 6) N ] + 2Q H = 0.25 inch or 0.15L where L = Length of symbol H = Height of symbol C = Number of data characters N = Wide-to-narrow ratio X = X dimension (narrow element width) Q = Quiet zone [2:1 to 3:1 with X>0.02 inches] [2.2:1 to 3:1 with X<0.02 inches] [Minimum inches] [0.25 inch with X<0.02 inches] Code128: L = (5.5D + 11C + 35) X + 2Q H = 0.25 inch or 0.15L where L = Length of symbol H = Height of symbol X = X dimension (narrow element width) C = Number of total ASCII characters, including function characters and necessary shift characters D = Number of data characters in numeric field Q = Quiet zone [Minimum inches] [10X] 14 Based on infromation from Austech Development, Inc.,