Modbus

[Embedded]

OK I see, here's a new server with some input knobs and graphs.

I've limited the array size to 1000 in the server to keep the processing down.

Also here's the current Client (with both tx led's fixed).

also I've sent these to HQ who have also posted the EXE's in the Examples section:

http://www.dsprobotics.com/support/viewtopic.php?f=11&t=231

[fixstuff555]

Wonderful job. The server works great! These are great additions to flowstone...

[Embedded]

Thanks, it was a team effort!

I'd like to get some hardware to play with do you have any recommendations?

[fixstuff555]

I have used this company's stuff in the past. It's really inexpensive, and seems to be decent.

http://www.tri-plc.com/nano10.htm

They make OEM style embedded plc boards, that aren't real fancy, but make decent io boards for pendants, operator control panels, etc. The price on the Nano 10 is pretty good at $130. It has a built in web server also. Not much IO, but the built in RS485 port can be useful also. Thats about the cheapest Modbus TCP client/server board out there.
Theyre biggest board model is this one:

http://www.tri-plc.com/fmd88-10.htm

Its a lot more ($289) - but its actually only $190 or so once you buy the kit. It has a ton of IO on it.

You might find some used bus couplers and such on ebay or something pretty cheap also like this one:

http://cgi.ebay.com/Phoenix-Contact-FL-IL-24-BK-PAC-Modbus-TCP-2862314-/170598283570?pt=BI_Control_Systems_PLCs&hash=item27b8733932#ht_2404wt_1139

But that one needs an IO slice. Those also have a webserver in them usually. I have used tons and tons of Phoenix Contact hardware. Its really good, but this stuff is usually pricey - even used.

FInally, I have used these as well.

http://www.anybus.com/products/products.asp?PID=90&ProductType=Anybus-IC

Its a chip module in a 32 pin DIL format. This is about $80 or so. It has two output methods, 16 byte in/out direct with no programming (SSC shift register) or 128 byte in / out using SCI using Modbus RTU. The serial interface is the most flexible, and thats what I used. The direct one is the easiest though with 8 words in/out - almost matching up with your modules you wrote. One thing of note: most people don't realize it, but in the industrial world HMS has stuff EVERYWHERE. They build the communications front end for a ton of other manufacturers. They make top notch quality stuff. Only problem with it is you'd have to bundle buffering circuitry with it. It's TTL, and pretty forgiving, 5V powered and all, and you have to get an RJ45 socket with it. Its got a web server also.

Not sure what your electronics background is, since a chip may not be what your after. Overall I'd say the two I'd recommend is the Nano-10 if you want a ready to use module, or the Anybus IC if you can handle chips and whatnot.

[Embedded]

Cool thanks!

FYI I am an qualified Electronics Engineer, so chips are ok too...

[fixstuff555]

Well then I would probably recommend the Anybus IC. It's the cheapest of the bunch, and is capable of being "embedded" in designs very easily. One nice thing about the Anybus chip, they not only have Modbus TCP, but I believe that the same chip does Ethernet IP and regular TCP/IP as well. They also have other protocols as well, and the same interface to the microprocessor side. Develop that (which is Modbus RTU btw) and it will work with all of their other protocol chips which are pin compatible with each other. This gives manufacturers instant connectivity to a bunch of industrial networks, without having to redesign the interface for every protocol. I used the chip with Profibus in a pendant years ago, when Profibus was my preferred industrial fieldbus. Another cool thing is you can monitor the data either via the wbe server or the built in serial diagnostic port, which is handy.

On thing of note, HMS looks to be moving away from the DIL IC format somewhat. Not sure how many more years they'll keep it. Their next gen modules are way more powerful, so I'm sure it will happen sooner or later.