10 OPC UA VariableTypes ToC Previous Next

10.1 ProcessDataVariableType ToC Previous Next index

This VariableType is used to represent the process data input and output of an IO-Link Device. The Properties defined by this type define the length of the Variable as well as a descriptor of the structure. The ProcessVariableType is formally defined in Table 58.

Table 58 – ProcessDataVariableType Definition

Attribute Value        
BrowseName ProcessDataVariableType        
IsAbstract False        
ValueRank 1 (1 = OneDimension)        
DataType Byte        
References Node Class BrowseName DataType TypeDefinition Modelling Rule
Subtype of the BaseDataVariableType defined in OPC 10000-5.          
HasProperty Variable ProcessDataLength Byte PropertyType Mandatory
HasProperty Variable PDDescriptor Byte[][3] PropertyType Optional

The read-only Variable ProcessDataLength is representing the structure ProcessDataIn defined in IO-Link Specification, B.1.6, and contains information about the length of the ProcessData. The value (one byte) shall directly be mapped to the Byte DataType.

The optional read-only Variable PDDescriptor is representing the structure PD Input Descriptor or PD Output Descriptor defined in IO-Link Common Profile, B.5.2 and B.5.3. The value shall be mapped to an array of an array of Bytes of length three.

NOTE: The PDDescriptor defines the structure of the ProcessData by defining the data type, length and offset in the data of potentially several data entries in the ProcessData (see IO-Link Common Profile). It is not further mapped to OPC UA information (e.g. by providing sub-variables for each entry with the concrete value based on the ProcessData) as this can potentially change dynamically and this is not recognizable in time by the OPC UA Server.

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