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From Julian Feinauer <>
Subject AW: Symbol metadata for connections
Date Sat, 02 May 2020 09:05:51 GMT

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).

Von: Christofer Dutz <>
Gesendet: Donnerstag, 30. April 2020 22:32
An: <>
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?


Am 30.04.20, 21:54 schrieb "Łukasz Dywicki" <>:

    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,

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