Hi, but we should make it compatible with all protocols (in theory) so we shouldn't name things with OPC UA as reference and try to map things to that. Would be cool if someone could describe how this mechanism works in the different protocols and how the operations are named.
Chris Am 02.05.20, 11:06 schrieb "Julian Feinauer" <[email protected]>: Hi, this is a very good point. You mean something like "getAllSymbols()" (which would only be possible in S7 case with either TIA File or S7Comm+ Protocol). But totally makes sense for ADS or OPC UA. Would love to see a Design Doc for that (starting with OPC UA and ADS gives quite a wide range of needs). Julian ________________________________ Von: Christofer Dutz <[email protected]> Gesendet: Donnerstag, 30. April 2020 22:32 An: [email protected] <[email protected]> Betreff: Re: Symbol metadata for connections Hi Lukasz, Initially we were planning on supporting a "browse" functionality alongside the "read", "write" and "subscribe" ... might that be more what you are referring to? Chris Am 30.04.20, 21:54 schrieb "Łukasz Dywicki" <[email protected]>: Hey, I been going through some ideas what could be improved here and there after doing my ADS try outs and come to following. Current API for PlcConnectionMetadata offers few basic canRead, canWrite, canSubscribe methods. It does not offer any api to read plc kind or symbol, even if some drivers do discover device kind. For comparison, with JDBC, we have few more options when we fetch metadata - ie. java.sql.DataBaseMetadata#getTypeInfo, #getTables, #getColumns and so on. I tend to opt for TypeInfo and Columns (symbols) as first class citizens which we can make. Currently protocols which can handle metadata requests can not support discovery of available symbols cause there is no way to supply that. This is something possible with ADS, for sure also with OPC UA. It shouldn't be to hard to provide one. Best regards, Łukasz
