Some restrictions exist regarding the Attributesof a VariableTypeor a Variableused as an InstanceDeclarationwith regard to the data type of the Value Attribute.

When a Variableused as InstanceDeclarationor a VariableTypeis overridden or instantiated the following rules apply:

  1. The DataType Attribute can only be changed to a new DataTypeif the new DataTypeis a subtype of the DataTypeoriginally used.
  2. The ValueRank Attributemay only be further restricted
  3. ‘Any’ may be set to any other value;
  4. ‘ScalarOrOneDimension’ may be set to ‘Scalar’ or ‘OneDimension’;
  5. ‘OneOrMoreDimensions’ may be set to a concrete number of dimensions (value > 0).
  6. All other values of this Attributeshall not be changed.
  7. The ArrayDimensions Attribute may be added if it was not provided or when modifying the value of an entry in the array from 0 to a different value. All other values in the array shall remain the same.