DDE to Siemens AS511 or RK512


Thread Starter

Ruben Dario

I´m intersted in a DDE application for AS511 or RK512 PLC SIEMENS protocol , does anybody know any DDE of this not too expensive ?..

Gerry Baduria

DDE is a Microsoft Windows functionality. As far as I know you can only make use of it if you are running an application on the MS Windows operating system. DDE can be used on a single computer where 2 applications will be sharing data. For instance, you can have Siemens WinCC acting as DDE server and MS Excel acting as a DDE client, both running on the same computer. In this case you can have WinCC data be viewed dynamically at Excel. Or these same applications may be ran in 2 different computers with Windows operating system and still communicate via DDE (using NETDDE.EXE, etc.).

Lately, I was able to communicate successfully 2 computers via DDE. One is running a Fix Intellution with Fix DDE server (under Windows 3.11) and another with Siemens WinCC under Windows 2000).

You cannot use DDE directly on a PLC with only AS511 or RK512. These are incompatible protocols to DDE. Work it out with something that works on Windows. Good luck!

Gerry Baduria

Donald Pittendrigh

Hi All

Any DDE application designed for Siemens PLC serial connection using P3964 or P3964R should work as the syntax of the protocol has been retained. The serial comms as used with S5 PLC's is not entirely complete for S7 PLC's as it is not possible to ask for DB's exceeding 255 and the same limitation applies to counters, timers and flags if I recall correctly, but within these limitations it should be O.K.

Donald Pittendrigh