The revision attributes include the major and minor revisions, which are combined to create a sequence. The revision scheme defines a valid sequence for these attributes.
There are three types of revision scheme:
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Sequence - The sequence type allows revisions to increment sequentially through an explicit revision code list until that list is exhausted, at which point no more revisions are available.
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Repeating sequence - This uses an incrementing, alphabetic revision sequence. Because of its repeating nature, the repeating sequence type supports only single revision characters separated by a comma. However, as the revision number repeats through the list after the first time, revision code 'AA' and so on are allowed.
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Numeric - The numeric type increments sequentially from 1 to infinity, though the initial revision can be specified as a default value. The sequence field should either be blank (indicating that revisions increment from 1) or contain a single numeric value from which subsequent revisions are incremented.
If the numeric type is used, two additional parameters are required to determine revision codes: field size and pad character. The field size defines the minimum number of digits to be presented in the revision.
If the revision does not meet the minimum number of characters, then the pad character is added to the left of the field until the minimum is reached. For example, a numeric revision scheme with a field size of 1 and no pad character would result in the following revision: 1, 2...9, 10, 11...99, 100.... A numeric revision scheme with a field size of 2 and a pad character of 0 (zero) would result in the following: 01, 02...09, 10, 11...99, 100....
A single revision scheme can have a combination of revision types applied to it.
For example, a single revision scheme can have a major sequence with a repeating type
sequence and a minor sequence with a numeric type.
The revision scheme for a document must be determined every time a revision is created, including when you create a new document or new revision of an existing document. The revision scheme of a document may change from one revision to the next, if, for example, that document is revised from a plant configuration into a project configuration. When a project revision is merged back to the plant, it can either retain the revision details it had in that project or take the next available revision at the plant, as dictated by options on the Merge command. This is described in more detail in How to Configure Concurrent Engineering.
The system needs to be able to configure a revision scheme by:
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Document class, for example, for or template documents. This is optional and indicates that the revision scheme applies only to documents with a given interface and that documents with that interface can use only that revision schema, or any others related to its other interfaces (that is, it cannot use revision schemes on interfaces of other documents or revisions schemes not related to an interface).
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Configuration level, for example, A, B, C at the plant level and A1, A2, A3 in the project.
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Configuration item, for example, in Plant A or Plant B.
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Document classification type, for example for 3D documents.