Model-Based Definition > Geometric Dimensioning and Tolerancing Advisor > GD&T Advisor > Introduction to GD&T Advisor > DIN ISO Standards Reference Notes
DIN ISO Standards Reference Notes
In order for the designs to be interpreted properly, it is important that the design data includes references to the applicable standards. Designs based on the German edition of the ISO Geometrical Product Specification standard may require the following standards references:
DIN EN ISO 1101:2014-04 — This is primary ISO GPS standard (German edition). It invokes geometrical tolerancing and a number of related ISO GPS and drawing standards.
DIN EN ISO 8015:2011-09 — Invokes the independency principle and requires the specification of a standard (e.g., DIN ISO 2768) to specify general tolerances.
DIN ISO 2768:1991-06 — Invokes general geometrical tolerances and may invoke general linear and angular tolerances and the envelope requirement.
General geometrical tolerances tolerance class indication (H, K, or L) is required.
General linear and angular tolerance class (f, m, c, or v) may be specified.
The envelope requirement (E) may be specified.
DIN ISO 16792:2008-12 — Invokes the digital product definition practices standard.
DIN EN ISO 286:2010-11 — Required when the design model includes table-driven tolerances; invokes the ISO code system for tolerances on linear sizes.
DIN EN ISO 10579:2013-11 — Required for non-rigid parts.
In addition, a notation is required that indicates the linear units for the model.
DIN standards are as shown below, where # represents the standard number and YYYY-MM represents the publication date.
DIN #:YYYY-MM is used for German standards with primarily domestic significance or designed as a first step toward international status.
DIN EN #:YYYY-MM is used for the German edition of European standards.
DIN ISO #:YYYY-MM is used for the German edition of ISO standards.
DIN EN ISO #:YYYY-MM is used if the standard has also been adopted as a European standard.
One common source of confusion is in understanding which ISO standards apply to the design model and which versions of each of the applicable standards is appropriate. The stems from problems with the way ISO standards are developed:
ISO standards are short, individual documents
The releases of ISO standards are not synchronized
ISO standards are divided into many single-topic standards. A separate ISO standard covers profile, another covers positional tolerancing, another covers datums, and so on. The result is a collection of small standards that must be synchronized to be usable in industry. However, it is very difficult to keep all of the individual ISO standards in sync with each other. When one standard changes, it may define, use, or replace terms that were being used in another ISO standard. To further complicate the situation, standards reference other standards that have been withdrawn. This leaves the user confused on which standards really apply to the design model.
The standards themselves allow the applicable standards to be indicated in a vague manner. In some cases, a standard must be specified directly in the design model (e.g., ISO 8015). In other cases, standards are invoked by another standard that is indicated in the design model (e.g., ISO 3040 is invoked by ISO 128-24, which is invoked by 1101, which is invoked by ISO 8015 being indicated in the design model).
The ambiguity regarding which ISO standards apply is a major source of confusion and risk. For this reason, GD&T Advisor automatically generates notations in the design model that indicates the standard and its revision date that is invoked by the design model.