IEE1394/ Modbus TCP/IP

R

Thread Starter

R A Peterson

A friend of mine not on the list has been sent a piece of equipment that he needs to communicate with. He says the instructions that came with it say he can communicate wia IEEE1394 or Modbus TCP/IP.

He is looking for some more information on the protocals involved and hopefully some code snippets. He mentioned he'd like to have them in C++ for a Unix system
 
C

Curt Wuollet

Hi;

I'll bet he's working with an Opte22 Enet rack. If so, the IEEE1394 they talk about is a block
transfer protocol using IEEE1394 defined packets on top of TCP/IP. Lots of information in the
Ethernet Brain Users Guide and Programmers guide on opto's website. www.opto22.com.
They have some Linux code for the IEEE1394 proto thay use. I have a Linux userland bootp that they sent me so you don't need a windows box to set the IP. I have started working with this beastie. The best place for starting code on the Modbus side is Modicon's examples @ www.modicon.com/openmbus. There's code in C++, C, and Java. If it's not the Opto22 stuff, please let me know what it is, because I'm currently working on a Modbus/TCP driver for the Linux PLC and would like to have it work for as many vendors as possible. Watch this list for progress on my driver. As soon as I have something working
he can have that. It'll be in C though.

Curt Wuollet
Wide Open Technologies.
 
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IEE1394 = FireWire

Try this link:

ftp://ftp.symbios.com/pub/standards/io/1394/P1394a
www.ti.com/sc/1394

Modbus/TCP is well documented try any of the following

www.modbus.org
www.modicon.com/techpubs/toc6.html
www.modicon.com/techpubs/toc7.html
www.modicon.com/openmbus/
www.robustdc.com/mbus_tcp.htm

(credit to Rob Hulsebos for the Industrial Networks web link list which I
have found very handy)

> ------- Forwarded message follows -------
> From: [email protected]
> Subject: COMM: IEE1394/ Modbus TCP/IP
> To: [email protected]
>
> A friend of mine not on the list has been sent a piece of equipment that he needs to communicate with. He says the instructions that came with it say he can communicate wia IEEE1394 or Modbus TCP/IP.
>
> He is looking for some more information on the protocals involved and hopefully some code snippets. He mentioned he'd like to have them in C++ ofr a Unix system
 
S
On Mon Jan 17 20:56:30 2000 Curt Wuollet wrote...
>
>www.opto22.com.
>They have some Linux code for the IEEE1394 proto thay use. I have a Linux
>userland bootp
>that they sent me so you don't need a windows box to set the IP.

This is the second time I have seen this go by, and my curiosity is stirred up.

Why won't the standard bootp daemon work here?

--
Stan Brown [email protected] 843-745-3154
Westvaco
Charleston SC.


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C

Curt Wuollet

Hi Stan,

The explanation I got (I was also curious) was that the Linux bootp sends a packet with an IP in it, which the "Brain" rejects. This did
not make a lot of sense since that is kinda the idea of bootp. So I put this off until I can read the RFC and sniff the exchange and see if it's a Linux problem or a Opto problem. I would bet on the latter since they have their own server on win9x also. Perhaps they are accomodating someone's broken bootp. The Linux server
they sent does work and came with source, if you want a look. They said it was "freeware" whatever the hell that means. They responded with it very soon after I ragged on them about having to screw around for a whole day and wreck a perfectly
good system to have a Win98 box I needed for 2 minutes. I consider that very good service.

Curt Wuollet
Wide Open Technologies


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P

Phil Covington

Curt:

It may be that the Opto brain expects bootp packets from linux with a destination IP address of 255.255.255.255 Linux insists on changing
255.255.255.255 into the local subnet broadcast address which the Opto brain rejects.

One possible work around is to create a host route from your network interface address to 255.255.255.255. This might work:

> route add -host 255.255.255.255 dev eth0

Bootp will then send its BOOTREPLYs to 255.255.255.255

Phil Covington
vHMI

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1394, invented by Apple and turned over to IEEE, is a serial I/O interface used in the commercial/consumer space for connecting computer peripherals - especially high-speed devices such as video camcorders, audio recorders, and
external storage devices. IEEE 1394 is commonly referred to as FireWire (as originally designated by Apple), or i.LINK (a Sony branding initiative). The theoretical limit for the bandwidth of a FireWire interface is 400 Mbps (or
50 MB per second). At CES the 1394 Trade Association announced that the 1394b version of the IEEE standard, running at 800Mbit, is ready for market.

A FireWire bus is self-powered (FireWire peripherals can derive power from the bus, eliminating the need for a separate power cord); it configures itself automatically (not requiring device IDs or terminators); and it is hot-pluggable (one can connect and use a FireWire peripheral via a simple modular connector without having to restart the computer). Besides very high
bandwidth, easy of use, and hot-pluggability, a key enabling feature of FireWire is isochronous(real time) data interfacing between nodes. An
isochronous data transfer occurs in a one-to-one or a one-to-may fashion and may use up to 80% of the available bus bandwidth. For example, realtime
video and audio can be transferred from a digital video camera to one or many computers on the bus. No error correction nor retransmission is
available for isochronous transfers which, of course, is no big deal for audio/video, but I'd certainly imagine any process control usage will be limited to asynchronous mode.

Resources (in addition to the TI site mentioned previously):

http://www.chipcenter.com/networking/ieee1394/main.html (Excellent!)
http://www.1394ta.org/ (1394 Trade Association Home)
http://www.embedded.com/1999/9906/9906feat2.htm (Embedded Systems's
Fundamentals of FireWire)
http://www.zayante.com/Sum9903.pdf (A summary (PDF) of the existing 1394
standard)
http://24.1.208.115/1394informer/ (A FireWire news page)

Mike Ryan
Aerojet Fine Chemicals
 
A
Check out the "Black Box Pocket Glossary of Computer Terms", pg. 90. You may want to call their technical staff as well. "A standard for serial- bus architecture, developed by Apple as Fireware, which supports a maximum data rate of 100 Mbps."

Regards,
Art Bourdeau,
[email protected]
Phone:(518)765-3667
Fax: (518)765-4033
Mobil: (518)573-4745
Fax:(518)765-4033
web: www.bcsco.com
 
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