Microcontroller communicate with Profibus

Hi experts,

Please give me inputs on how to design a microcontroller based device as a slave to an existing Profibus-DP system.

I have a MP377 (WinAC MP, Profibus-DP Master) +ET200S system, now I'd like to add a self-designed microcontroller based device in the profibus so the MP377 can give instructions to the microcotroller.

I know the hardware of profibus is RS485, does it mean if I have a RS485-RS232 converter connected to my controller then I can program this controller to communicate to the profibus? If so, any examples of the programming would be greately appreciated.

Best regards,

You need details on the Profibus protocol. You can either get that information from the source, PI, or you can reverse engineer it.

If you go to the Profibus.org web site, the downloads dealing with the technical aspects of implementing Profibus are designated as "for members only" with membership in the Profibus organization needed to access the files.

Generic user documentation is there for free download.

http://www.profibus.com/nc/downloads/downloads/-82b8f0269d/list//none/

Thank you for this very valuable website.

I read a few articles and i was right about the RS485-RS232 converter, now I am looking for proper microcontrollers and sample codes.

Best regards

Get a Siemens Profibus DP development Kit

That is what we did way back in the 90s. The Profibus-DP development/starter kit includes a 8051 and the software drivers. We ported the code to a 80186 and later to other more powerful micro controllers.

We were the first ones in West to pass the profibus-dp certifications on the first try. We had people calling to ask how we did it but it was easy when we started with something that was already working.

The starter kit cost $2500 back then but every time you took your product to Johnson City it cost $3000. Some failed many times and would have been better off paying for the development kit.

Hi!

Could this be something for you? I think there are some common genes with VIPA.

http://www.profichip.com/products/overviewasics/?PHPSESSID=57f529458887ff0ca28ecd747332afb5

Kalle

Edit: Check the evaluation kits. Can possibly save you for a lot of work.

Kalle, one still needs to write code for those profichips. I think they are designed to be drop in replacements for the Siemens SPC3 so I bet the code required to drive them will be similar. I wouldn't be surprised if we used a few of those profichips on some products.

I think Profibus DP will die a slow death like Modbus Plus. 12 Mbs is not fast any more. One top of that Profibus DP doesn't interface nicely with modern CPUs. Back in the 1980s Profibus DP was fast enough to keep up with 8 bit micro controllers. Now it is a pain in the a$$ to interface these chips with a modern 32-64 bit micro controller. First, the Profibus chips must be accessed 8 bits at a time. Second, the micro controller must insert many wait states for each access. It simply ties up the modern micro controller for two long to access each byte and wastes bandwidth and CPU power.

Ethernet is the way to go and if more speed is required then 1GB Ethernet is available although no one in the industrial world is jumping on that yet.

AlecTek, this is a big undertaking if you are doing this for just one device.

Edit, I just found out we use the VPC3+B. It works like the Siemens SPC3 so I know there will be no short cuts.

Thanks, Peter! Informative (as always)!

Kalle