Electronic – Adding Profibus capabilities to a product

microcontrollerprofibusprotocol

We are currently developing a product and now the "idea" has come up to integrate Profibus since it is quite used in that specific area. Now I was wondering if anyone has made such a product. If I understand correctly, Profibus is actually a RS-485 bus with some additions (especially in layer 2).

According to my research, our device would probably be a DPV-0 slave (Slave device, cyclical data exchange). We are intending to only produce low quantities of this product (max. 200 pcs / year). The whole product is a small sized machine, cost will be around 1k-2k €/pc.

Two options exist:

  • Implement the protocol stack in software and be limited to lower baudrates + the risk of not being fully standard conform.
  • Buy a specific IC, e.g. the VPC3+S from Profichip and only handle the required part manually

Now for the actual questions:

  • Will we need to be a Profibus Member to sell our product?
  • As far as I understand, every manufacturer needs to create a GSD file for his product, are there any tools available for creating this file?
  • How can I easily set up a test environment?
  • Are there any other fabricators of Proficbus ICs compared to Profichip (not only RS-485 transceivers)?
  • Has anyone already implemented the protocol in software? What were the main challenges?

Best Answer

Following this link you will find profibus software implementations in assembler (AVR) and C (AVR and MSP). Speed is up to 187.5kBps, but using XMEGAs I guess that few higher speeds would also be possible. beware that with software only implementation and without being a member, it will be hard to certify your product officially (which may or may not be important to you).

If certification does matter, then it's easiest to use some already certified Profibus chip. At this link you will find AVR and 8051 example interfacing VPC3+C Profibus chip.

You can download GSD editor here.

For testing, there was free PC software (if you can't google it then let me know and I will check my notes) that allows you to do the testing even with 9.6 and 19.2 Kpbs, which means that you don't even need any special card (except RS232<>RS485 convertor), since these are standard speeds available on PC. For more serious testing you need to have a professional equipment like Procentec ProfiTrace. It is very powerful but very expensive.

If you need consulting services, then let me know with a private message.

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