This is a subtype of the UInt32 DataTypewith the OptionSetValues Propertydefined. It is used to indicate how the Valueof a Variablecan be accessed (read/write), if it contains current and/or historic data and its atomicity.

The AccessLevelExType DataTypeis an extended version of the AccessLevelType DataTypeand as such contains the 8 bits of the AccessLevelType as the first 8 bits.

The NonatomicRead, and NonatomicWrite Fieldsrepresent the atomicity of a Variable. In general Atomicity is expected of OPC UA read and write operations. These Fields are used by systems, in particular hard-realtime controllers, which can not ensure atomicity.

The AccessLevelExTypeis formally defined in Table 41.

Table 41– AccessLevelExType Definition

Name

Bit

Description

0:7

Formally defined by the AccessLevelType in Table 40.

NonatomicRead

8

Indicates non-atomicity for Read access(0 means that atomicity is assured).

NonatomicWrite

9

Indicates non-atomicity for Write access (0 means that atomicity is assured).

WriteFullArrayOnly

10

Indicates if Write of IndexRange is supported.

(0 means Write of IndexRange is supported)

11:31

Reserved for future use. Shall always be zero.