"Why is this function not implemented"
Because it's very difficult to implement it, since it "violates" the client/server rules.
A server sends a reply to a client's request, with this function the server sends cyclic unsolicited data after a "setup" telegram.
To accomplish this, a further thread should be attached to the worker thread.
Since WinCC 7, as far I know, is the only system that uses this mechanism the answer to the second question is : maybe never ;)
Regards
Davide
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I know this is an old topic, but I'm still struggling with it. Not only with WinCC but also when trying to use a "variable observation table" (don't know the exact English name for it) in SIMATIC Manager. Both use cases are - of course - noted as not implemented on the Snap7 Server page:
Cyclic data I/O
The server does not replies at all.
As far as I have understood the information given by the WinCC help, the PLC could always deny the request to use the cyclic read methods. Wouldn't it be a good thing to implement such answer as the default response to the request? Or is the content of that response yet unknown?
Regards
Max
Last edit: Max Senft 2018-07-13
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We want to connect from Simatic WinCC 7 to Snap7 Server.
While using our default TCPIP connection we get this error message from Sanp7 server:
"Function group cyclic data not yet implemented"
When "Zyklusbildung in AS" is deactivated in System Parameter TCPIP it works.
Why is this function not implemented and whill it be done in a future version?
Last edit: Johannes Kayser 2015-07-06
"Why is this function not implemented"
Because it's very difficult to implement it, since it "violates" the client/server rules.
A server sends a reply to a client's request, with this function the server sends cyclic unsolicited data after a "setup" telegram.
To accomplish this, a further thread should be attached to the worker thread.
Since WinCC 7, as far I know, is the only system that uses this mechanism the answer to the second question is : maybe never ;)
Regards
Davide
Hi,
I know this is an old topic, but I'm still struggling with it. Not only with WinCC but also when trying to use a "variable observation table" (don't know the exact English name for it) in SIMATIC Manager. Both use cases are - of course - noted as not implemented on the Snap7 Server page:
As far as I have understood the information given by the WinCC help, the PLC could always deny the request to use the cyclic read methods. Wouldn't it be a good thing to implement such answer as the default response to the request? Or is the content of that response yet unknown?
Regards
Max
Last edit: Max Senft 2018-07-13