Devicenet for Dummies

Hey guys and gals. I've recently been "given" a section of the plant that uses Devicenet and I don't have any experience with it. I have tried searching here and thought maybe that Ron B. might have weighed in on this topic but to no avail. I have also Googled it and while I found alot about CAN bus systems there doesn't seem to be any info on HOW to program with it. I think that I have figured out a little but have no confidence in that knowledge and nothing to practice on as yet. The zoo keepers here are not going to come up with any training and the only other person here with knowledge is busier than a one legged man in a you know what contest.

Any help or direction at all here would be greatly appreciated. Thanks to all responders.

try here first...

http://www.odva.org/Home/ODVATECHNO...ceNetTechnologyOverview/tabid/72/Default.aspx

Thanks but that was one of the first places that I looked. I have a poor understanding of networking after only taking one online class. I understand some of the principles and the layers of protocols but have no hands on experience. I guess that I am trying to get my head around some things.

1. Does the module act like a switch in that it takes incoming messages, stores that message and then sends it on to the desired address on the CAN bus trunk?

2. In a ladder, the addresses for the Devicenet have 1747-SDN under the instruction or output. I know that this is the module being addressed but I can't quite grasp how it is being utilized. A discreet input to the plc and an output with the previously mentioned 1747-SDN under it. Does it just convert it to a CAN protocol then broadcast it to the correctly addressed device?

3. Are any of my assumptions so far correct or am I still not there yet?

The DeviceNet protocol is based on the CIP protocol. You will find most documentation mixes the CIP terminology with an abstract terminology that was created to help make it easier for end users. Until you find the need to do advanced things, don't pay too much attention to references of objects, instances, classes, etc.

The two things that you only really need to know about are Polled data and Parameters. Polled data is updated coninuously and automatically, this is the IO you see. Parameters are typically setup information that only needs to be sent once to the device. These need some ladder code to read and write.

A very useful tool to start with to learn more about DeviceNET is RSNetworks for devicenet.

Here's a free demo. See link below

http://www.koldwater.com/downloadlinks.htm

Craig,
Have you opened up your configuration with RSNetworx for DeviceNet? How your device net nodes operate within your SLC is dependent on how your system is configured. I would suggest going into your configuration offline and looking around a little. If you open up your configuration, you should see a representation of your network nodes and be able to view the properties of each. The area I think you are interested in is your SDN configuration in which you can see how the different devices are assigned to inputs and outputs and what if any devices may be comming in via M registers.

Investigate this a little and then I think you will be ready to come back with a whole new set of questions we can help with.

Oh and by the way you probably will develop a strong dislike for Device net with any long term experience. I refuse to spec it, but it seems like all our clients have it.

Russell

Here's an AB manual

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/dnet-um072_-en-p.pdf

Thanks to all.

Micky, I checked out the manual and the free 3 day demo and even contacted Koldwater. $129 for the liscense is a bit more than I can spend right now but I saved it for a later time.

Archie and Russell, you have both given me some more food for thought. I don't have the RSNetworx for Devicenet yet so I will be making a trip back to the front office to try and pry that out of the death grip of the IT manager. A previous machine manufacturer, that is no longer in business, once told me that CC-Link is like Devicenet so I'm hoping to kill 2 birds with one big rock.:site:

Thanks again everyone. I'll definately post back with a new thread as the wave of questions start.

Throwing this out:

http://rockwellautomation.custhelp....td_adp.php?p_faqid=44883&p_created=1192560736

It says at the site this is the former Devicenet Bible.

When you get the RSNetworx for Devicenet loaded on your computer in the help files there is a tutorial that may be of help.

Phil Melore puts out a newsletter that you can receive free. He wrote a couple of letters on DeviceNET basics a while back, but I lost some E-mail files and no longer have those. Maybe someone else still has a copy.

Over the years, Phil has covered just about all the commonly used communications protocols in his newsletters.

To get Phil's great letters, go to "Profile, then "Edit Options", then select "Receive E-Mail from Administrators".

Thanks Lancie. I already recieve those newsletters but I don't think I have them either. I'm pretty well convinced that I will have to stand in the IT line and wait till my number comes up.

Thanks again everybody.

The Tutorial slideshow that comes with RSNetworx for DeviceNet is very good for general information about the network and the role that the RSNetworx software plays.

Get the user manual for the scanner you're using and print out the I/O table addressing for reference.

Sign up for the DeviceNet newsletter that John Renaldi sends from RTA Automation.

http://www.rtaautomation.com/devicenet/

I'm a big DeviceNet fan and have sold and commissioned thousands of nodes, mostly in MCCs.