This abstract DataTypedefines a value that can have any valid DataType.

It defines a special value null indicating that a value is not present. This abstract DataType does not have an encoding defined in OPC 10000-6. Any direct subtype shall only be defined in NameSpaceIndex0.

A BaseDataTypeis an abstract DataTypewhich represents any possible value including arrays of values. When an array of BaseDataTypesis specified each element of the array can be a scalar or array of any DataType.

When a BaseDataTypeis used in conjunction with a ValueRankthen the ValueRankspecifies whether there is an array of BaseDataTypevalues. The ValueRankdoes not restrict the content of each element.