we discussed OptionSets based on the OptionSet DataType today and came to several conclusions:

• The length of the ByteString in the OptionSet shall be for default the number of used bits + the offset to fill full Bytes (e.g. 1 Byte for 3 bits, 2 Bytes for 10 bits).
• Subtypes of a concrete subtype of OptionSet shall not change the length anymore!
• The length of an OptionSet can also be defined explicitly by a new defined optional Property on the DataType NodeClass (e.g. OptionSetByteStringLength, which is similar to MaxByteStringLength on Variables, but defines the length always to be used). So each concrete OptionSet DataType has a fixed length. The Property allows defining an OptionSet that may have subtypes with additional bits.
• As stated currently in the 1.05.02 RC the structure of the structured DataType OptionSet shall never be extended. However, a subtype may add additional bits as long as it does not exceed the length of the ByteString defined in the supertype. In the Subtype, the OptionSetValues shall repeat or refine all entries of the supertype and may add additional entries. A refinement of a bit may be to change from "Pump is off" to "First Pump is Off", but not to something completely different like "motor is on".