Hi all, Sebastian and I just had a little off-list discussion and I’m taking this back to the list to get your opinion.
The issue we were discussing is that for example in the S7 driver, we are mapping all supported PLC4X datatypes to corresponding S7 datatypes. Now there are generally two options: * For every driver, create code to map all PLC4X supported datatypes to corresponding datatypes * For every driver to use only the supported types and to throw exceptions for all unsupported ones. Now I definitely generally favor the first option. As it’s one of PLC4X’s unique selling points that you can write code for any PLC without knowing the details of the protocol used. This would be violated by the second option, in my opinion, because changing from S7 to Modbus for example would require a change of code, if we were reading a Byte for accessing the 8 Boolean digital input values at once. If a user wants to for example write a Byte, Integer, Double to a Modbus Coil (Boolean), then I think PLC4X should map a single byte write request into 8 Boolean ones (The larger ones mapped accordingly). Regarding Floating-Point numbers and Time values however I would not 100% insist on this, because not all PLCs support these and converting a Double into a Boolean pattern doesn’t really make sense, same with converting a Time into a Boolean value (Converting this into an Long however could make sense) What do you others think? Chris
