Networking Communication with Profibus

  • Thread starter KARTHIK KRISHNAN
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Thread Starter


I want to connect a PLC with PC using Profibus network. Should i install any software for Profibus ??? what is the process of connecting the PC with PLC using Profibus??

Umesh Satyanarayana

Visit Allen Bradley or GE fanuc web sites. You will get more details. Basically you need software (developed by PLC provider) thru which u can assign DI's DO's or even monitor events, in general u can do communication.
Umesh S
San diego, California.

Keith Baldwin

Typically for Profibus you buy a high speed (up to 12 mbaud) communications card that plugs into the ISA or PCI slot. The board will come with the software that you need. Some suppliers include:

There are other options available to go out the serial port in case you don't have an ISA or PCI slot. I would not recommend PCMCIA due to overheating and cable failure problems.::

Keith Baldwin

James Ingraham

You will need a Profibus card. I assume that your PLC will be the Profibus master, in which case you need a Profibus slave card. Or you could buy a Profibus master card and then get a DP-DP bridge.

Almost all Profibus cards either come with or have the option for an OPC server. My personal pick is Synergetic; the OPC server comes free with the card. Also, all (or virtually all) of the Profibus cards on the market come with a .dll if you want to write VB of C++ code to talk to the card.

Prolinx Gateways (among others) makes an Ethernet to Profibus converter, instead of having an ISA or PCI card. Any Modbus/TCP or Ethernet/IP OPC server would work. You can write your own Modbus/TCP or Ethernet/IP software in VB or C++ if you like.

When people say Profibus, they typically mean Profibus-DP. Note that Profibus-DP is not like Data Highway+ or Modbus Plus. It is strictly cyclical data. Profibus-FMS adds the capability of peer-to-peer messaging, but the same rules apply; buy a card and use OPC or write code with that calls the .dll.

-James Ingraham
Sage Automation, Inc.

Daniel Chartier

I see basically two levels to your question, and the answer to one will affect the other.

First, how are the PC and PLC related over Profibus: which is master,which is slave, or are they both masters? And are we speaking of Profibus-DP (it could be FMS, FDL...) Requirements for each will change with your decision.

Second: as with all communication issues, there is a hardware and a software configuration. On the physical level, both the PC and the PLC require a Profibus ASIC (chip) in their makeup. I presume the PLC is already a Profibus master/slave.

For the PC, there are many companies offering Profibus interfaces (Siemens, Softing, SST, Applicom,... see "": for more details). Each of those companies also offers accompanying software to set-up the interface to the network as master or slave;

I suggest you buy the appropriate software once you choose the card. Then there is the issue of what software you will use on the PC to connect to the setup card: OPC client, HMI/SCADA sotware, VB script... Each possibilty requires an evaluaton of requirements. The software chosen must have some form of driver to hook up to the interface.

Just make sure that every level of your network interface is covered when you make your purchases. It is a lot easier to cover your ground earlier in the project.

Hope this helps,
Daniel Chartier