The WriterGroupId with DataType UInt16 is an identifier for the WriterGroup and shall be unique across all WriterGroups for a PublisherId. All values, except for 0, are valid. The value 0 is defined as null value.

The WriterGroupId shall be within the range 0x0001 - 0x7FFF for external assignment by configuration tools, and 0x8000 - 0xFFFF for internal assignment like through the Method CloseAndUpdate of the PubSubConfigurationType.