====== IEC 62541-008 OPC Unified Architecture - Part 8: Data Access ======
[[dido:public:ra:xapend:xapend.b_stds:tech:iec:start| return to the IEC Standards ]]

<table>
<caption>Data sheet for OPC Unified Architecture - Part 8: Data Access</caption>
| Title                      | OPC Unified Architecture - Part 8: Data Access |
| Version                    | 2020|
| Document Number            | 62541-8|
| Release Date               | OPC Unified Architecture - Part 8: Data Access  |
| Reference                  | [[https://webstore.iec.ch/publication/61117]] |
</table>

  : **Note**: The following is an excerpt from the official IEC catalog. It is provided here as a convenience and is not authoritative. Refer to the original document as the authoritative reference.

===== Abstract =====

IEC 62541-8:2020 is part of the overall OPC Unified Architecture (OPC UA) standard series and defines the information model associated with Data Access (DA). It particularly includes additional VariableTypes and complementary descriptions of the NodeClasses and Attributes needed for Data Access, additional Properties, and other information and behaviour.

The complete address space model, including all NodeClasses and Attributes is specified in [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-3]]. The services to detect and access data are specified in [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-4]].
This third edition cancels and replaces the second edition published in 2015. This edition constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous edition:
  : a) added new **''VariableTypes''** for **''AnalogItems''**;
  : b) added an Annex that specifies a recommended mapping of OPC UA **''Dataccess''** to OPC COM **''DataAccess''**;
  : c) changed the ambiguous description of **''"Bad_NotConnected"''**;
  : d) updated description for **''EUInformation''** to refer to latest revision of **''UNCEFACT''** units.

See also:

  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-1]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-2]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-3]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-4]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-5]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-6]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-7]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-9]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-10]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-11]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-12]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-13]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-14]]
  * [[dido:public:ra:xapend:xapend.b_stds:tech:iec:62541-100]]

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