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3.4.3.3 Variables

For all Variablesspecified in this specification, the Attributesnamed in Table 5shall be set as specified in the table. The definitions for the Attributescan be found in OPC 10000-3.

Table 5– Common Variable Attributes

Attribute

Value

MinimumSamplingInterval

Optionally, a vendor-specific minimum sampling interval is provided

AccessLevel

The access level for Variablesused for type definitions is vendor-specific, for all other Variablesdefined in this specification, the access level shall allow a current read; other settings are vendor specific.

UserAccessLevel

The value for the UserAccessLevel Attributeis vendor-specific. It is assumed that all Variablescan be accessed by at least one user.

Value

For Variablesused as InstanceDeclarations,the value is vendor-specific; otherwise it shall represent the value described in the text.

ArrayDimensions

If the ValueRankdoes not identify an array of a specific dimension (i.e. ValueRank<= 0) the ArrayDimensionscan either be set to null or the Attributeis missing. This behaviour is vendor-specific.

If the ValueRankspecifies an array of a specific dimension (i.e. ValueRank> 0) then the ArrayDimensions Attributeshall be specified in the table defining the Variable.

The concrete array length is contained in the delivered Value. Therefore this information is only relevant for write access to the Variable Valueif the array has a fixed length.

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