To access POWERLINK Objects on a Server, which represents only one POWERLINK Object Dictionary the size of the NodeId is 4 byte and the format is defined in shown in Table 48.
Table 48 – NodeIds for single instances
|0||LSB of the objects POWERLINK Index|
|1||HSB of the objects POWERLINK Index|
Byte 0, 1 and 2 are the values of the POWERLINK addressing scheme Index / Sub-Index. If the POWERLINK Object requested by Index/Sub-Index is not existing the server shall signal this case with the StatusCode Bad_NodeIdUnknown.
With byte 3 the client specifies the expected DataType of the response data by using the built-in types defined in OPC 10000-6. Allowed values are 1 to 12, as well as 15. If byte 3 is set to 12 or 15 (String or ByteString) the server shall respond with the same length like the POWERLINK Object. Otherwise, if the bit-length of the referenced POWERLINK Object is different to the bit-length of the requested DataType, the Server shall signal this case with the StatusCode Bad_NodeIdInvalid.