This part of IEC 617 forms an element of a series which deals with graphical symbols for diagrams. The series consists of the following parts:
— Part 1: General information, general index. Cross-reference tables;
— Part 2: Symbol elements, qualifying symbols and other symbols having general application;
— Part 3: Conductors and connecting devices;
— Part 4: Basic passive components;
— Part 5: Semiconductors and electron tubes;
— Part 6: Production and conversion of electrical energy;
— Part 7: Switchgear, controlgear and protective devices;
— Part 8: Measuring instruments, lamps and signalling devices;
— Part 9: Telecommunications: Switching and peripheral equipment;
— Part 10: Telecommunications: Transmission;
— Part 11: Architectural and topographical installation plans and diagrams;
— Part 12: Binary logic elements;
— Part 13: Analogue elements.
The scope and the normative references for this series are given in IEC 617-1.
Symbols have been designed in accordance with requirements given in the future ISO 11714-11). The module size M = 2,5 mm has been used. For better readability smaller symbols in this standard have been enlarged to double size and are marked "200 %" in the symbol column. To save space larger symbols have been reduced to half size and are marked "50 %" in the symbol column. In accordance with the future ISO 11714-1, clause 7, symbol dimensions (for instance height) may be modified in order to make space for a greater number of terminals or for other layout requirements. In all cases, whether the size is enlarged or reduced, or dimensions modified, the thickness of the original line should be maintained without scaling.
The symbols in this standard are laid out in such a way that the distance between connecting lines is a multiple of a certain module. The module 2M has been chosen to provide enough space for a required terminal designation. The symbols have been drawn to a size convenient for comprehension, using the same grid consistently in the representation of all symbols.
All symbols are designed within a grid in a computer-aided draughting system. The grid which was used has been reproduced in the background of the symbols.
The older symbols which were included in appendix A of the first edition of IEC 617-9 for a transitional period, are no longer part of this second edition, as they will definitely be withdrawn from use.
The indexes in Annex B and C include an alphabetic list of symbol names and their corresponding number. The symbol names are based on the description of the symbols of this part. A general index including an alphabetic list of symbols of all parts is given in IEC 617-1.
1) At present, at the stage of Draft International Standard (document 3/563/DIS).