Unbiased opinions- AB ContolLogix and Motion


Thread Starter


I've been involved with Motion Control for the last 18 years. I've always worked for companies who either manufacture or use traditional, stand alone Motion Controllers.

I have not had the opportunity to employ an AB ControlLogix platform for Motion Control and I'm interested to hear the pros and cons from those who have?

Bob Peterson

I have had only limited experience with the CLX motion control stuff. For single axis control it works no better (or worse) than an SLC HSRV module. It runs rings around the old IMC junk.

For coordinated motion, it seems OK if there is some reason you want to do it in the PLC instead of in a motion controller. Cost wise it is more or less a wash.

Personally, I prefer having a seperate drive with built in controller, like an AB Ultra series drive.

Trevor Ousey \(list\)

We have implemented both the 1756-M02AE and 1756-M08SE (and a 1756-M16SE) with older Siemens and Rockwell servo drives. Some of the applications have been simple position servo and then complex position/velocity loops on a converting line replacing mechanical cams. The product has matured quite well and with the release of version 16 there are some excellent new

One of the oddities we came across was the homing function, it has issues if you use software limits, and we had several packaging line that were upgraded to CLX motion where they each would act differently during the home/start position routine yet all had the same logic. Our last upgrade was to change a lineshaft machine to sectional drives, and we wanted to try using 1756-M02AEs with closed loop vector Powerflex700 drives. This was implemented quite easily.

Things to be aware of is the timing for the axis, there are some technotes available on this. Overall it is relatively easy to implement.

Marc Sinclair


I have priced up several AB control logix motion control (servo) systems, but never built one because of the prices. Luckily in Europe there are lots of other options available.

Marc Sinclair
I came from the same arena - motion controller or controllers separate from the rest of the logic. I became a complete convert when I discovered that it was possible to control motion and all the other process logic on one PC. Doing coordinated motion, camming, gearing, became trivial.

The pros:

* All the trajectories, all the data, everything is in one spot with one clock (the PC CPU) - no handshaking of information, no cross referencing of variables and data.

* Synchronous coordinated motion of many axis is not as difficult.

* One software package to handle motion and sequential (traditional PLC) logic.

* An OS (Windows) that allows other programs, HMI for example, to run. Log data easily. Network with other controllers. All the goodies associated with having an ubiquitous platform.

* in general much less $$$

The cons:

* You have to be very careful about communicating with the drives. You need a deterministic bus, e.g.. SERCOS, EtherCAT, Powerlink, or fast analog outputs, encoder inputs.

* You need to synchronize the motion task to the fieldbus cycle. Some packages are better than others. Caveat Emptor.

* You have agree to running a machine with a Windows PC. As long as I treat the PC as an industrial controller doing motion - that happens to run Windows, but mostly it is an industrial controller - if I treat it as this, and not a PC like we normally do, I have zero problems. I will blank out the tool bar, the Start menu, and even the Windows boot up splash screens. I will chose a PC that doesn't even look like a PC at first glance. As far as the end user is concerned, it is a controller - not a Windows based PC.

* ControlLogix is not the only platform, there are others that have employed the philosophy of doing motion and closing the servo loop at the PC for years. Other packages also are more open to using other vendors for axes. No one company can do everything the best. If you want to know more, email me privately at bob<remove>@<remove>mindspan.us

Robert B. Trask, PE
San Diego, CA

Rokicki, Andrew (Andrew)

I have similar experience as you. Using stand alone controllers and than recently ControlLogix controllers (1756-M02ME). For simple applications such as point to point, constant velocity motion, gearing it is fine. But if you need to do something more complicated it is too "dumb down".

Pro: integrates into their PLC, simple to use.
Cons: expensive, insufficient documentation. Does not have most of the features of stand alone motion controller.


In my "unbiased" opinion, AB have always been followers in Motion Control and Drive Systems. Take for instance the recent V16 motion "improvements" 3 axis inverse or forward kinematics--other motion vendors have had this for years to a decade or more! Take for instance the afterthought of a system you can build with PowerFlex 700S/DriveLogix drives.

I sat in an AB CLX Motion class among ten other companies being represented and they all had problems with their motion systems that AB support has been unable to resolve (including me), but in the next sentence they (but not me) would state that they love to do motion control in ladder logic. So there is your pro--people who don't really understand the fundamentals of motion control doing motion control in ladder logic. I have seen OEMs that build systems with AB's CLX motion who don't understand the fundamentals of following error and torque loops.

In an AB Integrated Architecture brochure referring to drives I read a line like this: "Easy-to-use tools require no specialized knowledge", so I interpret that as "with our easy-to-use tools we can make an engineer out of any idiot." Sounds like a great Dilbert.

I have a list a mile long why I don't like AB motion, but I am not interested in helping them design it for the better. They aren't paying me for that. I have found many a limitation where other systems could have handled it without any extraordinary work or effort.

Think about the problems you have had to solve over the last 18yrs then sit down and figure out how to do it with the CLX motion (or more like how it probably won't work as good as you did it before) and you will understand where I'm coming from. Then sit down and evaluate the cost--sure they will sell the first system cheap to get it in the door, but from then on you're hosed... and yeah, for a simple or small system it isn't too bad, but even then I would rather just use an intelligent drive and a comms bus to talk to it.

I will repeat this--the only pro that you can find out there, and that they will sell you on is the integrated architecture--they let you do motion in the PLC. Like I said, the con list is a mile long, and the con to their only pro (integrated architecture) is that when you go to make a change down the road get the anesthetic out because it going to be painful.

My version of integrated architecture is buying a motion controller or drive system that can directly talk to any PLC (AB or other brands) via ControlNet, Profibus, Ethernet, etc. so I have a black and white line where I can cut the umbilical cord. Not so with AB's integrated architecture--try changing/retrofitting to a different brand of drive one day on an AB integrated architecture systems--you won't find the umbilical cord much less be able to cut it. Take for instance how well they have done with RSView Enterprise series and the Factory Talk--boy they have their agenda and people are buying it... scary how tightly integrated it's going to be, too.

I have a lot of AB CLX motion, and other AB drives/motion (PowerFlex 4, 40, 700S, 1394, Ultra 1000, 3000, Kinetix, M02AE, DriveLogix)--over 300 axes worth--so consider yourself fortunate to not had to work with it in the past 18 yrs. Run from it and embrace something better.

BTW, you aren't going to find an unbiased opinion, even mine, my opinion is biased by pure experience of real motion controllers and drive systems, and those who pretend to be.

So if the AB integrated motion architecture is the approach we should take then as a country we should send our entire paycheck (not just the 30% or so now) to the federal government and let them spend it for us. I mean we got enough AB shoved down our throats why would I want hand more of it to them? So it can be screwed up too? No I am not bitter, AB just makes other motion and drive vendors look like geniuses when it come down to it!

Michael Batchelor

We have placed one Control Logix Motion system, actually two controllers on a single assembly station, and honestly, it works extremely well.

That isn't to say that it didn't take a lot of work to get it there. There were issues of firmware revisions, incompatibilities between one software interface package and another, ya-da, ya-da, ya-da. It was *NOT* and easy task to get going correctly. But there isn't any reason to assume that A-B won't work those issues out. The early days of the PLC-5 were ragged, too.

Regardless, now that it is in place, it really does work very well.

As always, the name on the front costs extra, but it was a customer requirement.

Was it worth it? That's a harder question to answer. Obviously our customer thought so, because they specified it. And it certainly does give you a "one stop shopping" option. We would at least put it on the table to evaluate on the next job that requires motion control, but I would not automatically default to using it nor automatically exclude it.

I know that isn't exactly a glowing recommendation, but those are the facts. I suppose the best thing to say is that A-B wanted in the motion control game, and now they're in the game. They may not be taking home the pennant next year, but they're in the pro league.

Michael R. Batchelor
I think that was about as unbiased as one can get about AB.

Anyone that uses AB motion and drive products tends to do so primarily because it says AB on it, rather than any other reason.

By the way, any one else here use AB Powerflex 40P positioning drives? I want to cry over a product that has so much potential and yet was implemented to make it so difficult to use in any application other than the one they targeted.