SLC 5/05 via Ethernet Controlling Powerflex40

I have a 5/05 frn 10 and rslogix500 ver 7.10 and I am trying to start/stop a Powerflex40 drive. I can read and write parameters with a EEM instruction but I can't fiqure out how to start and stop the drive. I see that i need to alter the control word in the drive but where do you do this.

Thanks in advanced for any help!

There is a discussion about this topic somewhere around here, but basically this is not something you really want to do with a SLC. It comes down to that fact that the newer SLC firmware says that you can do EtherNET/IP (or whatever the correct capitalization is for that), which many people take as being able to do IO control over ethernet. That is not so. If you read the fine print you will find that this only means the SLC can do CIP (control and information protocol, I think) MESSAGING only. You can actually do this as a message, but if your PLC, switch, cable, etc become damaged the drive will not stop since you are messaging the commands to the drive. With a ControlLogix family processor you actually take control of the IO on the drive, like with DeviceNet. So the drive is able to know when it has lost it's master and it can shut-down, fault or whatever you set up in the ethernet module on the drive.

Of course I am sure that Ken Roach can explain this much better than I.

Darren

Found what I was looking for.

For an almost identical question with links to A-B tech notes see:

http://www.plctalk.net/qanda/showthread.php?t=20724

For other info realated to I/O and the SLC 5/05 see:

http://www.plctalk.net/qanda/showthread.php?t=22941


Hope this helps,

Darren

AB has redone the knowlege base. The new link to the SLC to PowerFlex message is:

http://rockwellautomation.custhelp.com/cgi-bin/rockwellautomation.cfg/php/enduser/std_adp.php?p_faqid=28652&p_created=1085457600&p_sid=3cOQe7pi&p_accessibility=0&p_lva=36236&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MSZwX3Byb2RzPTAmcF9jYXRzPTAmcF9wdj0mcF9jdj0mcF9zZWFyY2hfdHlwZT1hbnN3ZXJzLmMkZG9jbnVtZnVsbCZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PUE4MzI1MDI0Mw**&p_li=&p_topview=1

I second not doing this with the SLC. It is very DANGEROUS. Hardwire your start/stop

I suppose I just can't talk people out of this.

Have you sent a message to set the Comm Fault timeout value of the 22-COMM-E to a nonzero value ? This value is represented as N42:3 in the PCCC object, and as Class 0x04, Attribute 100 of the Assembly Object.

How many drives are you trying to control ? What else is on the network ?

I actually did get it up and running with the msg instruction and am working on doing it with the EEM instruction. Yes I did set N42:3 to 5 seconds first and sent a stop command. I am running 8 drives and there is probably 35 nodes(mixed) on the net. As far as loss of communications goes, as long as the parameter is set to fault or stop that shouldn't be an issue. I have verified this by pulling it off the switch.

You put a lot of faith in technology. Please tell me you at least have a real Estop circuit

I still recommend against using this method to control drives.

Consider what may happen if your SLC runs out of TCP connections that it can handle continuously. The -L553 and -L552 can handle 24 simultaneous connections, the -L551 only 16 (last time I looked). A common way to consume TCP connections is to autobrowse with RSLinx, or leave a diagnostic webpage open, which are not under the control of your user program.

Consider what will happen if one of the drives is replaced or set to defaults. Will your logic re-set the communications timeout value ?

Consider what may happen if one of the drives is programmed to the incorrect IP address. Does your logic check the drive's identity before starting the motor attached to it ?

What happens in your logic when a drive is disconnected from the network ? Do messages continue to be triggered to it ? Are they removed from the SLC message queue, or is there a point where the queue will be filled up if too many drives are unplugged at the same time ?

All of these considerations are for functions that the EtherNet/IP scanners in the Logix family (and the ControlNet and DeviceNet and RIO scanners for the SLC) have built in, and the SLC-5/05 MSG instruction lacks.

If you're looking for further help with the EEM instruction, post what you've tried and what results you've had.

Thanks Ken for your thoughts. I have not worked with drives on the net before and thought that loss of comms wasn't a huge issue were the drives will take themselves down if that condition exists and I can always chesk status bits for functionality. But you do make good points. TWControls, actually I have a virtual E-Stop it is connected to port 42685 it is opened on my firewall if you would like to try it. I was just asking a question. I am not an idiot. It seems silly that my local AB distributor would tell me this is the thing to do. I had reservations about it from the beginning and that was part of the reason for joining and asking this question. AB is actually promoting this issue with SLC 5/05 frn 10 and RSlogix 500 ver 7.10 to communicate and control powerflex drives via ethernet and the EEM instruction.

I don't mean to bend someones nose, but I would only expect to be treated with the same respect i would extend to them.

I haven't heard any distributors suggesting using this to control drives but if they are it needs to stop.

But still just because someone suggest something like this it is up to you to determine if it is a responsible thing to do. And this is dumber than hooking your E-Stop to port 42685. Why? Because the Estop is a joke, your setup is dangerous and has a possibility of getting someone hurt or killed.

But go ahead and just smart off instead of trying to listen to someone who is trying to help you keep your application and those who use it safe.

Obviously you care more about making a dollar than making a quality product. And your application tells us what you think of others lives

Okay, fellas, deep breaths.

Shawn, lots of us come from industries where people can get hurt or killed when controls fail. I am both fortunate and cautious about this sort of thing, which is why I do not recommend control using messaging. It's too easy to screw up.

For all we know, your application involves variable speed baby-food warmers.

I'd like to make a couple of disclaimers.

Rockwell Automation does have a few technotes about the fundamentals of this feature in PowerFlex 4-series and 7-series drives. That's not the same as "promoting" the feature as a substitute for a real I/O protocol. In fact, every article that I have seen shows read-only parameter data.

The customer I'm working with on this mechanism has hard-wired his Start and Stop circuits to I/O cards, and he has safety relays running a hardwired E-Stop circuit. That's the only reason I agreed to help him at all.

And now you have my curiousity piqued: What is a "virtual E-Stop" ?

Deep breathes done. I feel better. I just get worked up over safety issues such as that

The virtual Estop was pointed towards me

Ken, My application is quite simplistic, it involves a batching system for concrete. I am not controlling the drives for the critical parts of the operation(i.e. Mixer, High pressure water system), they are hard wired. It would be only for aggregate conveyors that are seperated from personnel and remotely watched by CCTV. Two AB Tech support guys have sent me example code both with MSG statements to write to data table N14:0 and N14:2 to start/stop and set speed reference. Although, this wasn't my real question to them it was to use the EEM instruction not the MSG instruction. Both tech guys are still using RSLogix500 rev 7.00 and haven't been giving the update yet and my understanding is that the EEM is on 7.10. I asked the tech support person his take on your concerns and he stated there are a lot of programmers using comms for start/stop.

There is no Virtual Estop, I was only try to point out to TWControls that that was an uncalled for remark. I am listening to everything people are telling me. Also, I am not making money on this I am the end user. I have been programming my own PLC's for years now. I like to know what is going on with the machines, that way I can fix them quickly myself.

My apologies if I offended anyone....