Code Resources

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Thread Starter

Alex Pavloff

Hey folks. I'm taking on the task of making some general resources for people writing communication code, with the intent of putting this onto the PLC archive. I'm starting with Modbus, so I've been looking around for all the Modbus info on the web. Modbus has a lot of information available -- a couple order of magnitudes more that every other protocol I typed in, so I can cull the info to come up with the "best of the web" modbus page. The first place to look is: "http://www.modbus.org/":http://www.modbus.org , and they have a fairly complete FAQ on Modbus TCP. No info on Modbus ASCII, Modbus RTU, or Modbus+... The protocol is very similar of course, but they don't say that. There are many links there I did manage to find a VB program that does Modbus, with some other useful links at "http://members.tripod.com/~mbserver/":http://members.tripod.com/~mbserver/ . So the first question is -- does anyone else know of any good links to Modbus resources that would be worth putting on a FAQ page? The second question is -- what other questions should be answered in a pan-Modbus FAQ? And the third question after that is... what other protocols would people like to see a FAQ/resource list for? I'm working in a nearly 100% serial world here, and so I'm not familiar with other fancy-schmancy wiring schemes companies have cooked up, and so I'm going to list the protocols that I know, and that I think should be looked at (in no order of significance whatsoever): Omron Hostlink Allen Bradley DF1/DH+/DH-485 GE-Fanuc SNP and SNPX Aromat MEWTOCOL-COL Seimen's MPI Koyo Directnet Mitsubishi FX Series (the exact name of protocol escapes me at the moment)

Thanks for any response:

Alex Pavloff
Software Engineer
Eason Technology
 
Alex Pavloff wrote: <snip> >Hey folks. I'm taking on the task of making some general resources >for people writing communication code, with the intent of putting this >onto the PLC archive. </snip> <snip> >So the first question is -- does anyone else know of any good links >to Modbus resources that would be worth putting on a FAQ page? </snip> Here's a link to Modbus Protocol Reference Guide on Schneider's website. It covers both Modbus RTU and ASCII. http://public.modicon.com/Public/Red/DocENG2.nsf/Default/D0B380D9BD65F F78852569CB00770EE5/$FILE/PI_MBUS_300.pdf Its a great document for all the Modbus fundamentals.
 
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Daniel Tsuruda

Personally I wouldn't waste time on most of the proprietary protocols as I think they'll be going the way of the dinosaur. Field bus on the other hand is the wave of the future. Daniel Tsuruda
 
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Joe Jansen/ENGR/HQ/KEMET/US

Maybe so with the heavily proprietary stuff, but saying that Modbus is going away is like all the 'industry pundits' that have been saying that ladder logic is going to 'go the way of the dinosaur'. The first time I heard that was in 1991, which is when I started writing ladder. I am still managing to pay the bills doing just that, though.... I guess that means that the PLCArchive (www.plcarchive.com) will soon become the PLC Museum..... (note the shameless plug..) $.02 --Joe Jansen
 
Your comment is confusing. Modbus is an OPEN protocol, and you said you wouldn't waste your time on the 'proprietary protocols'... Modbus is open, the protocol is available for download from Modicon, and it's supported by a large number of third party devices. Modbus would be an ideal protocol to implement for basic serial communications due to it's large supported base.

CK
 
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Adolfo Jimmy Saldivias

Daniel: We have taken note of your opinion. Now we will discard the note and ask you to gracefully step aside while Alex does this job, who needs most of all, encouragement. Alex, keep on the good work!!! Sites to visit: www.modbus.org This site lists a bunch of links at their website, among them: www.modicon.com/openmbus www.lancontrols.com http://www.eecs.umich.edu/~modbus/ http://www.robustdc.com/ http://www.industrialethernet.com/ http://www.iaopennetworking.com/ http://mbserver.w3.to/ http://www.win-tech.com/ www.calta.com http://www.automatedsolutions.com Hope this helps, Regards, MBA Ing. Jimmy Saldivias TECSIM Phone: 591-4-523438 Fax: 591-4-523413 http://tecsim.trading.net
 
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Alex Pavloff

Yeah, that would be nice. Too bad I don't believe for a second its going to happen. Ethernet and TCP/IP require protocols of some sort... you don't expect everyone to pile on the XML over HTTP (SOAP) bandwagon, do you? That would be too easy (not to mention the hardware/software requirements of putting an HTTP server and XML parser on every device is a little expensive). Special protocols will be around as long as we have networks.
 
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