Siemens MPI protocol


Thread Starter

S. Olinga


I want to write a MPI-driver in Delphi to communicate with a Siemens S7 plc. However, I can't find anything about the MPI frame and/or protocol. Does anybody has information how this works or where I can find this?


S. Olinga

P.S. In the past, I already wrote an unitelway driver for the Modicon TSX 37/57. So if anybody needs some information about this?

Thomas Hergenhahn

You will not find much, as Siemens doesn't publish the protocol.
You can get C source code for LINUX from my project:
It should not be too difficult to port it to Windows and Delphi.
If you do so, as it ist licensed under GPL, you are expected to publish your work also in form of sourcecode.



I think this will help a lot. However, I have no idea how long it will take before (or if) it's finished. Of course, publishing the sourcecode is not a problem!

S. Olinga

Mrozek Marcin

I would like to write an unitelway driver for Modicon under QNX in C++. I need any used information. If for you no problem to give me your code (in Delphi or diferent language) please send message via e-mail. If not - the frame of unitelway protocol schould be enought.


Mrozek Marcin PhD student
[email protected]
Why are you developing a thing that exists.
Look at my page
here you get all what you need. For Windows and LINUX.
For Siemens S7-300,400,200 MPI, PPI , H1 take a look an you might be surprised.
Save time and save money !!
A. Traeger