1、- EIA i188 57 m 323YbOO 0028627 8 m r - EB EIA STANQARD Engineering Department ELECTRQNOC INBUSTRUES ASSOCIATION EIA 188 57 3234b00 0028628 T W NOTICE EIA engineering standards are designed to serve the public interest through eliminating mis- understandings between manufacturers and purchasers, fac
2、ilitating interchangeability and improve- ment of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such standards shall not in any respect pre- clude any member or non-member of EIA from manufacturing or sell
3、ing products not conforming to such standards, nor shali the existence of such standards preclude their voluntary use by those other than EIA members whether the standard is to be used either domestically or internationally. Recommended standards are adopted by EIA without regard to whether or not t
4、heir adoption may involve patentson articles, materials, or processes. By such action, EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the recommended standards. I .: ?. . .1 Published by ELECTRONIC INDUSTRIES ASSOCIATION Engineer
5、ing Department 2001 Eye Street, N.W., Washington, D. C. 20006 Electronic Industries Association 1970 All rights reserved PRICE: 50c :. . Printed in U.S.A. EIA IBB 57 3234600 0028629 I STANDARD DIMENSIONAL SYSTEM FOR AUTOMATION REQUIREMENTS (Reaffirmation of RETMA Standard RS-188) 1. INTRODUCIION 1.1
6、 Scope: This standagd covers the establishment of a series of dimensional systems and nomenclature to serve as a guide in the coordination of equipment design and design of machinery for automatic manufacture. 1.2 Basic Module: In the design of electronic equipment which may be built on automatic ma
7、chines, it shall be standard to make all dimensions, which must be controlled for automation purposes, to be multiples of ,025 inches (.635 mm), that is decimal in form and English in units of length. This modular dimension shall apply to all three axes of Cartesian coordinates and shall apply to th
8、e following quantities among others: spacing between holes in printed wire boards, between matrix points in wire wrap, between leads in two or multi-leaded components or electron devices, spacing of terminals. or other types of larger components, overall printed board dimensions, lengths, test point
9、 locations, inter-board connections, etc. 2. GRID SYSTEM A For the dimensions that constitute the location of points of attachment of component and hardware, the following standards shall apply: 2.1 For Grid System A the preferred multiple of the basic module .O25 inches (.635 mm) shail be 4. This s
10、pacing of ,I O0 inches (2.54 mm) shall be used to form a coordinate grid of lines separated by .lo0 inches (2.54 mm). 2.2 be located at intersection points of said . 1 O0 inch (2.54 mm) grid. The points of attachment for at least one of the leads of each component or electron device shall 2.3 locate
11、d at intersection points of said .lo0 inch (2.54 mm) grid. To the maximum extent practicable points of attachment for all component leads shall be 3. GRID SYSTEM B For the dimensions that constitute the location of points of attachment of components and hardware, the following standards shall apply
12、: 3.1 For Grid System B the preferred multiple of the basic module ,025 inches (-635 mm) shall be 1. RS-188 Page 1 I EIA LB8 57 = 3234600 0028b30 = .e.- RS-188 Page 2 a This spacing of .O25 inches (.635 mm) shall be used to form a coordinate grid of lines separated by ,025 inches (.635 mm). 3.2 inte
13、rsection points of said .O25 inches (.635 mm) grid. The points of attachment for at least one of the leads of each component shall be located at 3.3 located at intersection points of said .O25 inch (.635 mm) grid. To the maximum extent practicable points of attachment for all component leads shall b
14、e 4. STANDARDS APPLYING TO COMPONENTS AND ELECTRON DEVICES For component lead spacing the following standards shall apply: 4.1 For the components or electron devices where the leads lie parallel to each other in a single plane at the point where they enter the mounting medium, the lead spacing shall
15、 coincide with any of a series of points separated by integer multiples of ,025 inches (.635 mm). 4.2 For components or electron devices where leads do not lie in a single plane the preferred lead position shall be such that the terminations shall coincide with intersection points of a .lo0 inch (2.54 mm) grid oriented wherever practicable, parallel to the major axis of the component. Where this is not feasible a secondary preferred lead position shall be such that the termination shall coincide with intersection points of an ,025 inch (.635 mm) grid. II y-
