UMENCHO

This is a very interesting issue. Frankly speaking I hoped that someone will give you that information. And then later, to ask you how is going the job. But it seems is not a public.
Sorry for OFFTOPIC.

Best regards,
Hristo MIhalev

smiffy

You will be extremely lucky to get this information.

smiffy

I expect that the backplane interface hardware and communications protocol are propriety to Siemens, and the information will not be available to anyone outside the design team.

smiffy

I myself work for Siemens (the power generation division) and even I would not be given this information.

smiffy

The only chance you have is that you discover that Siemens have used an industry standard for the backplane (e.g. VME bus, G64 bus etc.). You could then get the documentation for this industry standard.
.

smiffy

I wish you luck in your quest, and by all means keep us posted,.

smiffy

but alas, I think you are very unlikely to find success.

smiffy

Description

Software engineer for gas turbine manufacturing company.
22 years experience in applications, system and embedded controls engineering (mainly software).
Have designed and developed real time operating systems, device drivers, communications interfaces and compilers. Highly experienced in communications, especially modbus.
Experienced programmer in c, c++, ada, html, xml, assembler, SCL, UNIX.

dchartier

Hello Yogendra;
The backplane bus of the S7 CPUs is seperated in a P-Bus (peripherical bus) for high-speed digital signals and a K-Bus (same as your C-Bus, used for communications with CPs, FMs, and networks).

Here is the content of a German Wikipedia page (translated by Google):

K-Bus (SPS)

From Wikipedia, the free encyclopedia
The K-bus (also called communications bus) is a term coined by automation. About a K-bus there will becomprehensive exchange of data. In PLC technology, this bus, the task of exchanging data between the CPU of a PLC and its associated function and communication modules is realized.
The K-Bus is as an internal bus of a programmable logic controller (PLC) to see that no external interfaces have to. It thus serves only to transport the necessary quantities of data within a PLC. For the necessary communication between the CPU of a PLC and its affiliates and output modules, the bus has no meaning. This data exchange is the P-bus (peripheral bus).
Other discussions on P-Bus and K-Bus on the forum:

/tf/WW/en/Posts/51865

/tf/WW/en/Posts/6241

Hope this helps,
Daniel Chartier

AmirAlwaled

I love that very much I hope that I have CV like that some day I love your signature also

fritz

Hello AmirAlwaled
I'd say you can rest assured that the backplane P-bus (I/O bus) protocol is Siemens propietary and also that there are differences between the S7-300 and 400 at least as far a thebackplane K-bus (communication bus) is concerned (none of which will make your task any easier I'm afraid).

fritz

One additonal pointer I can give you though is to read Decinteresting research into this subject in the thread informations about backplane (S7 300 related).
While this, together with the other info you found, may give you enough starting points to do the reverse engineering of the backplane protocol, you will still have your work cut out for yourself.

fritz

Saying that, "value added third party" modules from other companies do exist (e.g. Helmholz offers CAN bus modules for the S7-300 which don't exist inthe Siemens portfolio) and these companieswould have the knowledge of the backplane protocol and may (but possiblymay not) be willing to share it.

fritz

My question to you is though:
Is it a must have that you hook your product/module onto the S7 backplane?
It may not only be easier, but would possibly also open you development to a wider market, if you instead develop it as a standalone module withlet's say Profibus or Profinet interface (which are open andwell documented interfaces).