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.