Devicenet/VFD/PLC Set-UP

I wanted to start using a Devicenet with my panel builds. Currently I build a panel to control conveyors. Very basic, start and stop. Just to transport product. What is the benefit of using a devicenet. Right now, I just adjust the speed on keypad. I use AB 160, AB Powerflex 4/4m/ Mits E700 drives. I use relay signal for the start and stop. I do have some sensors included for jam-ups and full status. CV's will stop and start based on the needs of production. Can someone give me some advice and maybe a good place to get literature. I am currently not a elctrician but have gotten a lot of projects that I have been handed to figure out.

Thanks
Jalopees

I would not choose DeviceNet because it is often difficult to troubleshoot. When DeviceNet works, it works great. When it doesn't work it can take a while to figure out. There are much better control networks available. If I were doing AB I'd go Ethernet, with Siemens I'd put the drives on Profibus. Just my opinion.

Jalopees,
The real benefit of DeviceNet is the reduced amount of wiring necessary to get full benefit of the drives capability along with status feedback from the drive.

All of the drive commands & feedback status bits are available by using individual wires for each one if your cabinet has room & you have all the I/O on the PLC to accept the inputs & the analog outputs to send the speed signals.

Setting up this type of system is not for the faint of heart or the beginner. It is very complex to get it all working correctly, but when done it only uses 4 wires to get all the communication going both ways between the PLC & up to 30 or so drives.

Usually the problems begin for the enduser whenever a device needs to be replaced. The new device needs to be configured in a certain way for this unique network or it won't play nice with the others on the network. Usually the new device has a different firmware revision, which requires the network scanner program to be edited to accommodate for the difference.

You didn't say which PLC you intend to use. If AB then I recommend you take a training course that is provided by Rockwell before going down this path.

Good Luck
BD

BD - much more specific information, kudos!

At GM we used devicenet extensively, and of all of the various systems that I've used, devicenet had not only the highest rates of breakdowns, but generally the longest length of breakdowns along with it.

I would avoid it if at all possible.

rootboy said:

At GM we used devicenet extensively, and of all of the various systems that I've used, devicenet had not only the highest rates of breakdowns, but generally the longest length of breakdowns along with it.

I would avoid it if at all possible.

Click to expand...

It is unfortunate that you guys have had all the problems with DeviceNet. We have been running several systems for a while now, the longest for over 5 years. No problems with the DeviceNet at all. This is all Allen Bradley hardware, and I have stayed away from the Vampire style connections. I use Thick Cable for the Trunk, and the Thin Cable for the Drops, using the AB DeviceNet Tap Terminals. I can't speak to the dependability of the Flat Cable with the Vampire Connectors, or the distribution methods.

I especially like DevicNet for VFDs, because of the access it gives to the Command and Status Words, and all the parameters. It also allows quick change out if a VFD fails. I have also used it quite successfully with Flex I/O as well.

Stu.....

Thanks BD, yes I am planning on doing that based on Rockwell Schedule. I am taking baby steps. Thanks for your input. My compnay is so outdated in software and PLC's. We use all types of PLC's from AB, Omron, Keyence, Mits, Direct Logic and I got thrown into to working with PLC's.I appreicate your insight. Thank You.

DeviceNet works great when implemented correctly. Those who cut corners on the physical media connections pay the price many times over. When Accounting runs Engineering, expect problems. These are just a few of the DeviceNet projects I have worked on:

http://www.joewazoo.com//network_DeviceNet_index.html

Joe_WaZoo

I think devicenet is great for drives. We have more than a hundred drives on a dozen or so devicenet networks and have very little trouble. The only problems we've had were self-induced with poor power supply connections and were not hard to troubleshoot.

We have 160 series drives, Powerflex 70, and Powerflex 700 drives and they all do quite well. The 160 series drives lose the HIM module when you put them on devicenet, so that is something to consider...All you get from the devicenet adapter is two LEDs, so your techs need a means of viewing faults, and monitoring remotely if you use those drives on devicenet.

We also have a SLC controlling a bunch of Powerflex 40s with ethernet messaging and it has been more trouble than devicenet. Ethernet/IP with a Controllogix PAC is fine, but in my opinion, is a potentially bigger can of worms to learn and troubleshoot than devicenet.

You can also use remote I/O for drives. I have several RIO drive systems running along with several devicenet systems running. I rarely work on them, but learning devicenet was much more difficult for me.

BEWARE THE DEVICENET!!!
As okie has stated if you are running a simple drive array then devicenet is pretty solid. However, If your like me and have huge conveyance systems with hundreds of photo eyes and hundreds of drives devicenet is the absoulte worst way to go. All it takes is for a photo eye to get hit by a fork truck driver or a case to fall on a cable or any other stupid thing to happen and the entire productiion floor and or warehouse goes down and I get to scramble around like a chicken with my head cut off. Even by looking for the faulted scanner it still dosnt really help narrow it down too much as I have 14 scanners and over 300 photo eyes and 150 drives spread out over thousands of feet of production and warehouse.
Devicenet is the bane of my exsistance. I hate it. I hate it. I hate it.

Go either net all the way. Cheaper, simpler, much, much more reliable.

Wow, Jim, it sounds like your networks needed a little better segregation. I agree that it's overkill for sensors, though.

answer DeviceNet

Hi All,

I am also a beginner to PLC's...... Actually, I have only been useing PLC's for about 6 months. I found it difficult to get people to show me what they know about PLC's so I went out on my own to find out more. I found an incredable amount of free stuff online. It also helped that I have a lot of knowledge about IT, cisco, microsoft, and basically know alout about computers and associated hardware.

DeviceNet is actually very user friendly if you appoach the concept the right way and learn its networking structure and software before damaging equipment. I found that DeviceNet is easier to install than wireing Flex drives to run via remote I/O or from older switching and relays.

If you want to learn DeviceNet the right way, go to Allen Bradley's website under the literature section and find "DeviceNet Communication" to download the awsome .PDF guide that they offer for free. You will thank me many times.

It discusses RS NetWorx in great detail, DeviceNet, and all the bells and whistles such as cable lengths, types of cable for certain applications, and how to install DeviceNet scanners, and VFD's I/O.

I think the hardest part you will have to understand is how to turn on the drives in RS Logix 5K and the appropriate addressing schemes with all the nodes on the network.

But Allen Bradley has made it very easy now because they came out with an Add-on that you can download for free to work with RS logix 5K that finds your DeviceNet scanner and all the nodes connected to it and it configures all the data types, I/O, messages, and BOOL automatically so you dont have to waste all the time to configure anything.

In addition, if you have to replace a drive, you can simply install the new drive, connect the DeviceNet cable, and instantly download all the parameters to the drive in less than 5 min from RS NetWorx software!

Dude, its easy, just look at the AB website, read, learn, then go to work and get paid to try it out!!

Good luck dude. Like I said I have been learning PLC's for only 6 months and I think I am actually better than the engineers that I work under.

also

I forgot to mention a couple things to look at....

You can find all this for free on the AB literature website. If you want to learn DeviceNet fast download these PDF's

DeviceNet Communications
RS Networks Install Guide
DriveExec Install Guide

And if you want to learn more about Industrial Network and Automation look at EtherNet/IP and ControlNet from the AB literature website. I mean, if you know anything about general networks this **** is actually very easy to pick up and understand.

If you are a younger guy like me (28) you have a huge edge on the old farts who still need to learn how to use the mouse on the computer befor even trying to understand Rockwell Software. Sorry guys, no offense but the younger generation is simply more trainable on this new stuff.

gOOD lUCK

If your entire network goes down ddue to a fork truck hitting a sensor, you got more problems than you think. First, you can only hook up 63 nodes per scanner so hundreds sounds rediculus. Also, DeviceNet uses a concept called the "Producer - Comsumer Model" Whiches allows for device failure without the disruption of the network. Perhapts you have some issues in your ladder logic that relies on that sensor that go broke for the rest of the program to function.

Im just sayn'.......