IEC 62027 pdf download

IEC 62027 pdf download.Preparation of parts lists
3 Definitions
For the purpose of this International Standard, the following terms and definitions apply. In the definitions, terms that are defined elsewhere in this clause are shown in italics . 3.1 General terms, related to structuring 3.1.1 object entity treated in the process of design, engineering, realization, operation, maintenance and demolition NOTE 1 The entity may refer to a physical or non-physical “thing”, or to a set of information associated with it. NOTE 2 Depending on its purpose, an object may be viewed in different ways called “aspects”. [IEC 61346-1, definition 3.1] 3.1.2 system set of interrelated objects NOTE 1 Examples of a system: a drive system, a water supply system, a stereo system, a computer. NOTE 2 When a system is part of another system, it may be considered as an object. [IEC 61346-1, definition 3.2] 3.1.3 aspect specific way of selecting information on or describing a system or an object of a system NOTE Such ways may be: – what the system or object does (function viewpoint); – how the system or object is constructed (product viewpoint); – where the system or object is located (location viewpoint). [IEC 61346-1, definition 3.3] 3.1.4 structure organization of relations among objects of a system describing constituency-relations (consists of/is a part of) [IEC 61346-1, definition 3.6] 3.1.5 reference designation identifier of a specific objec t with respect to the system of which the object is a constituent, based on one or more aspects of that system [IEC 61346-1, definition 3.7] 3.1.6 item reference number identification of component parts of assemblies and/or the identification of individual items on the same drawing [ISO 6433, clause 1] NOTE Item reference numbers are “document-based” as opposed to reference designations that are “structure- based”. Identical parts on a drawing are required to have the same item reference, preferably a number (according to ISO 6433), while each occurrence of an object in a structure is required to have a unique reference designation (according to IEC 61346-1). If a set of drawings for a product is structurally based on consist-of/is-part-of relations, item reference numbers are virtually the same thing as numeric product-oriented reference designations. 3.1.7 reference designation set set of reference designations of which at least one unambiguously identifies the object of interest NOTE Other members of the set need not necessarily identify the object of interest but other objects of which it is a constituent. [IEC 61346-1, definition 3.10]
Class A Parts lists in which each list item represents a type of constituent object and specifies the quantity of this. NOTE Class A deals with “summarized lists”; the quantity is often greater than one for each type, the part number of each object may be used as a ‘key’. This class of parts list is referred to as a “bill-of-material (BOM) data structure” in ISO 10303-44. Class B Parts lists in which each list item represents an occurrence of a constituent object. NOTE Class B deals with “detailed lists”; the quantity is in principle equal to one in each list item, the reference designation for the constituent object may be used as a ‘key’. This class of parts list is referred to as “parts list data structure” in ISO 10303-44. In cases where there is a need to specify a set of several identical objects, and if there is no need to distinguish between them in any context in the documentation, this set may be treated as one occurrence, in which the specified quantity is larger than one. Example: the hundreds of light-emitting diodes assembled to form a traffic signal. Class A parts lists are commonly used in mechanical design of discrete objects, especially if only one structural level is covered by the parts list. Class B parts lists are commonly used for electrical, fluid and other comprehensive systems, where there is a need to identify each occurrence of a type, for example for connection purposes. In this International Standard, requirements for both classes are specified.