I have used all these interfaces. Stay away from Interbus.. it is an older interface and has some issues.
Profibus is a very well defined I/O network. Properly setup it is very fast (up to 12 Mbaud) and reliable. Any number of protocols can be setup on it via bits, handshaking, and data exchange. It would be difficult to do a one-off Profibus interface for EMC2 and the interface cards are not cheap. Devicenet is similar to Profibus but not as fast and more bit oriented. If you want to pass several words of data, Profibus is a better fit. If you want to flip a few bits, Devicenet is fine. There is an open version of Devicenet called CanOpen and I have used that also. It works ok as well. Devicenet and CanOpen is typically quite a it cheaper than a Profibus implementation. Ethernet is a hardware specification. You can run all kinds of Protocols across it, including Modbus TCP. If this is a one-off job, and the welding robot does not have a Modbus TCP interface, or Modbus RTU interface available, I would consider buying a protocol bridge box. There are several of them available. They can bridge interfaces and protocols. For instance you could talk to it via the Modbus TCP master in EMC2 and out the other side the bridge box could appear as a Profibus Slave, or a DeviceNet slave, or as a master in some cases. These boxes aren't cheap. I think they are in the $1000 plus range, but they work. I've used a couple of different versions of the Anybus bridge devices. Their tech support is good. http://www.anybus.com/products/profibus.shtml?gclid=CJyL0rXL7KYCFUVqKgodpn_5BA One was a Modbus TCP slave to a Devicenet master. I think the other one was Modbus TCP slave to a Profibus Slave. I think that Blackbox is also selling a similar device, and there are others out there also. Beyond this, there are some software solutions out there also that will do a protocol translation via a single Ethernet port. For instances the Welding robot might like Ethernet IP, Rockwell's Ethernet Protocol. You send out Modbus TCP commands via a master (Like EMC2) and the ethernet device receives the Modbus TCP packets, does a translation, and then resends the message via Ethernet IP protocol back out the same Ethernet port. If you have a Windows Box available on the network, you can do that with an OPC data bridge setup. But that is not cheap either after you buy all of the software that is required. Dave On 2/3/2011 10:46 AM, Viesturs Lācis wrote: > Hello, gentlemen! > > I recall that ethernet as communication interface has been mentioned > here on this list, so I would like to ask anyone with experience in > this area to share it. > I would appreciate, if You could point me to some sources of > information - how it works, are there any different standards etc. > I have to establish a control over MIG welding machine, which is > designed for automated welding. Its manufacturer offers following > interfaces: > Interbus > Profibus > Devicenet > Ethernet > > My feeling is that using ethernet is best option (or even only option, > since I did not find any information about using EMC2 with those > remaining interfaces. I know that EMC2 can use Modbus). I would like > to find out, how it works, but all my attempts to search the web about > ethernet gives results of networking PCs. I tried different keywords, > but still the "curved hands" problem remains. > > By the way, does anyone have experience with Mesa 7I44 card? And where > could I find information about it? There is no manual in Mesa > homepage. > > Thanks! > > Viesturs > > ------------------------------------------------------------------------------ > Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! > Finally, a world-class log management solution at an even better price-free! > Download using promo code Free_Logger_4_Dev2Dev. Offer expires > February 28th, so secure your free ArcSight Logger TODAY! > http://p.sf.net/sfu/arcsight-sfd2d > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
