Standard for Logic Circuit Diagrams
|Publication Date:||1 January 1986|
(This Foreword is not a part of ANSI/IEEE Std 991-1986, IEEE Standard for Logic Circuit Diagrams.)
The contributors to this standard represent a broad range of institutions, technologies, and documentation needs. They include industrial, governmental, and educational organizations, producers and consumers of devices and equipment, users and nonusers of computer-aided design and drafting, and a range of aesthetic preferences. That a consensus of such diverse interests could be achieved in producing this standard is indicative of a need for a common practice in this field.
Work on this standard started in 1972, in an ad-hoc working group on Logic Diagrams, under the preparing group for Y14.15, Electrical Diagrams. Work was suspended for several years while the International Electrotechnical Commission, Technical Committee 3 developed Publication 117, Part 7. to which the United States contributed. In 1982 a new subcommittee was formed, operating as part of the IEEE Standards Coordinating Committee for Graphic Symbols and Designations, SCC 11. It decided to prepare a new draft incorporating:
1) The 1975 draft of the original working group,
2) IEC Publication 113, Part 7. insofar as practical (in the present standard, some parts and illustrations are very similar to the IEC document; differences and additions result from new developments in symbols for logic functions and new perceptions of current needs), and
3) Such parts of ANSI Y14.15-1968 (R 1973) as applied to logic circuit diagrams, but with updating to remove duplication of requirements found in referenced standards and to apply the material explicitly to logic circuit diagrams.
After ten drafts the present document was completed and submitted to the IEEE Standards Board for approval.
This standard provides guidelines for preparation of diagrams depicting logic functions. It includes definitions, requirements for assignment of logic levels, application of logic symbols, presentation techniques, and labeling requirements with typical examples. The techniques are presented in the context of electrical/electroni