Currently the Enumeration Data Type is defined through the EnumString property which contains a list of enumeration strings and the integer value of a variable is the index to the string array.

This does not allow the assignment of different values like it is needed for the NodeClass enumeration in Part 3 defining values of 1, 2, 4, 8, 16, 32, 64 and 128.

This feature is also needed for information model specifications like PLCopen where the standards or systems allow the assignment of enumeration values to enumeration strings.

I discussed this issue with Randy and our proposal is to define the following additional things:
(a) DataType EnumValueDataType defining a structure with Int32/SymbolicName/DisplayName
(b) Property EnumValues containing an array of EnumValueDataType
(c) An EnumerationDataType can have an EnumString property OR an EnumValue property

• If EnumValues is present the value is used to look up the string in the list.
• If EnumStrings is present the value is the index of the string in the list

In addition we should add this property to Part 8 MultiStateDescreteType.

We need also to change the data type of the MultiStateDescreteType from UInteger to Integer to be consistent with Part 3 / 6