RSLogix 5000 "Lock-Step" - What is this?

We have both Omron and AB PLCs in our plant. We are looking to standardize in the future on one platform. We have AB SLC-500 & PLC-5 along with Omron C200 alpha series. The AB guys have been telling me about the ControlLogix platform. It looks pretty cool, but I've heard rumors that the software and hardware don't always talk to one another. Something Rockwell calls 'Lock-Step' compatibility between hardware and software.

Does anyone know what this means exactly?

And, could you give me your input on going with the new ControlLogix versus Omron's new CS1 series PLC?

Thanks!

This is a MY plc is better than yours thing

Technically only you know what your systems would work the best with.
1. How many people in your organization are familiar with AB?
2. How many people are familiar with Omron?
3. How much of a learning curve will it be for those involved?
4. In your area who offers the best support? People that can actually offer assistance when needed.

This list could go on and on, write out the rest and use it as a guide.

Many here can state pros and cons of either but look at YOUR list to determine which direction YOU (your company) may want/need to follow.

ControlLogix5000 is very fastly adopted for PLC5 familiar peoples.
CS1 and CX-programmer are very familiar with earlyer families.
CS1 and CL5000 speed etc. are enough similar, but mathematics is more simple in CL, diffrent types of variables can very freely mix in CPT commands.

CL variable naming philocophy is something what i Love, you don't and you no need know anymore what is variable absolute address as N7:10.
Also You can do own Structures (as Timer is) and that is as Object Oriented programming !!!

They both are good choice, I like them both.

You have to admit "lock-step" sounded better than "goose-step".

Rockwell has released one or two major ControlLogix system functionality upgrades per year since Logix was introduced. Unlike some older controllers, programs compiled by the old compilers don't run on new firmware. Therefore your firmware in the controller has to be the same version as your software.

This is no problem if you can take the time to run the flash firmware routine when you get a new edition of the software, but it does pose some important challenges if you seldom shut down your controllers (like paper machines or generating stations that shut down maybe once a year at the most). It was difficult to deal with under Windows NT 4.0 as well because you couldn't install more than one version of RSLogix 5000 on a given PC at a time. That's no problem since Version 10 and Windows 2000 have become the prevailing installed base.

As for versus Omron CS1, I'm not the guy to ask; you'll have to find somebody who uses both.

CL

In my factory, there are recently 2 controllogix link on ethernet. One of them have 2 Dh+ network that link 25 AB plc's. With this configuration, we put information of many plc's on the ethernet network in our plan

Omron must be a good plc, but i did not worked with omron.

Wich one is the best? I don't know. But, for us, it was more intelligent to stay with AB plc to makes some scada on the ethernet network with RSVIEW. We have save many dollars.

Omron or AB, it depend of how many plc's you have with the same brand.

Thanks for some of your feedback.
And sorry, I probably should have provided more information for my second question (which is the better choice). I realize this depends a lot on information that you guys don't have.

What I really wanted to know is if anyone had experience with this "lock-step" thing in ControlLogix. Will I get burned by it? From what Ken said, it sounds like lock-step means:

1. HW firmware and SW revision MUST be the same
2. If they are not, I either have to:
a) flash upgrade (or downgrade) ALL my hardware to the same rev.
b) load multiple copies of RSLogix 5000 on my computer

Also, from seppoalanen, it sounds like Omron's new platform (CS1) is similar to their legacy stuff. And it sounds like the CLogix has a new tag structure from what he said (variable naming philosophy) with no absolute address. That kind of scares me for our maintenance guys. If I was an integrator I could see the advantage, but what if we have multiple companies building equipment for us? Will there be any consistency in the memory mapping? (i.e. right now I always know my timers are T4, counters C5, integers N7, etc. regardless of who does the job)

I'm starting to get some direction here, and thanks again for all your help! Any other comments or suggestions are welcome!

To change or not to change, that IS the question!

I agree with rsdoran on points he made. I remember the change over difficulties I had going from the early AB plcs that used octal addressing. When the PLC5 and SLC500 series came out, I was confused for a bit till I got over the differences. I think most factories today still have folks working that are better at the older plc language and have a time with newer ways. The Control Logix system is one I personally have never tried. Just never had the opportunity. I would not change to it from another just to change nor would I change to Omron, Mitsubishi, etc just to be changing. These changes may be easy for some, but a pure nightmare for others. Your support staff, store room, etc will be glad if you do not change.

At the OEM I work for, we just about exclusively use control logix... and for one reason, the intergrated servo control. Having said that, there is lots of other reason I would choose control logix over a SLC or an omron (although I have limited experience with omron). Personally, I prefer the tag based addressing, the the tasks/programs/subroutine setup lends its self very well to modular programs.

about the lock stepping, I dont really see it as a problem. If your going to change what version of the program your using, expect to spend some time downloading new firmware, lets just hope your using a ENET card!

Control logix addressing

I like the control logix alot we have about 10 of these processors running in our department along with lots of slc's and plc5. All are communicating through DH+, Ethernet, Devicenet, and (Profibus to a seimens micromatic drive). We are using version 6.00.0 really old I know. I love the capabilites that the CL has using motion instructions, as well as how simple it is to scale analog inputs/outputs and set your High high etc values I personally think that the conrol logix is geared more toward the programmer than the troubleshooter. Try finding what out the programmer named something in the program that you refered to as an @@@@@ etc. Another problem that we have ran into in using the CL is that we tried to update from version 6.00.0 to 8 or something like that and our motion instructions were all screwed up. anyway enough of this
Cya

Thanks Eastkodakguy!
This is what I seem to keep hearing! People love the capabilities of CL, but they have been screwed up by upgrading versions. It looks like a really neat platform -- especially the motion instructions -- I liked that a lot (seemed to make motion simple), but we're really not using too much motion!

With all that said, I'm concerned now about CL. If we have a module go bad and get another one of the shelf, it should be a quick and easy change out -- right? If I'm hearing everyone correctly, that is rarely the case with CL. I now have to make sure my old software and new hardware match. If I update to the new software, then my old hardware won't talk! When does this vicious circle end?

Am I overstating the situation? Is it really this bad?

Every new processor you recieve, you will have to flash. Every processor that currently has the wrong firmware for the version of RSLogixs your using, you will have to flash.

I work at an OEM, and dont have to deal with the after math, I flash a card once, and its done. Flash can take anywhere from a mintue or two (on ethernet) to probably 10 or 15 through your serial cable.

If I was to upgrade your plant, I think I would be inclined to to pick a version to use, and make sure every machine uses the same version to begin with.

I dont see the lock stepping really as THAT big of a deal.

Why were you considering Control Logix anyway? You said you guys dont really do a lot of motion, I know that if we built a machine without motion, I dont think we would be using control logix (because its more expensive than other platforms)

Reply to Steve Crotty

Steve - we are looking at CL because MOST of our machine builders have told us that we should be looking at this or Omron's new CS1 since we have some of both companies older CPUs and these systems are much more powerful than what I have now. Also noticed that my multipliers on the SLC platform were bumped up not too long ago -- I've already seen what AB is doing with the PLC-5 pricing (it is getting ridiculous), and I can only assume AB is going to force me to move sooner or later.

You stated that you work at an OEM and I should pick a version to use and make sure that they all match up front. I have a couple quick questions:

1. Can I tell my OEMs when they send in new equipment to use an older version (like 6.0 that Eastkodakguy is using?) to keep my entire plant consistent. Would that be too much to ask my OEMs?

2. With CL, is it only the CPU that I have to flash or do other modules require this?

The reason I ask this is that I spoke with my Omron rep yesterday. He came by to show me their new processor. It looks almost identical to what I have in the plant (the older C200 series), and he said that I can use my same software and also use my same power supplies, I/O cards, and networking modules that I already have as spares on the shelf. I asked him what he knew about CL, and he was pretty straightforward (or so it seemed). He told me that he thought with CL you had to flash upgrade other modules also (like analog cards or network cards). Is this accurate?

OK, I'm talking too much and need to shut up!

Here is something to think about (if you haven't already).

From an OEM standpoint, recommending the use of the latest versions of equipment is usually no big deal. After all, they gotta make changes like this all the time and, after all, all the new features are pretty nice. Issues regarding incompatibilities between software and hardware are just part of the territory.

Now, if you are an end user who does little in terms of troubleshooting or modifications, this might still be a good choice. Typically you will need to call in your OEM to do any upgrades or modifications or you will call in a specialist.

If, however, you are an end user who is frequently tweaking your processes and going on-line with your PLCs for troubleshooting, I think you will probably want to fall back a step or two from the latest and greatest.

In this last scenario, your plant-floor-kinda-guys are typically the ones who need to get on-line to troubleshoot and/or modify a program. Now these guys do not need to be concerned about versions and lock-stepping. What they need is to get on their systems every time. Of course this is compounded significantly with every additional PLC in the plant. All it would take is one or two machines being different from the rest (and inaccessible) to create the impression that your system is all messed up.

From my perspective, it sounds like you would probably do well to stay away from the ControlLogix if you are planning an all-out plant upgrade. Because you seem to be looking for system standardization rather than additional features, I don't think the potential for future lock-stepping problems is worth the new features that ControlLogix offers.

I can't speak to the Omron system because I don't know anything about it. But if your OEMs are recommending it, just be sure they aren't recommending similar kinds of problems.

Steve

1. Can I tell my OEMs when they send in new equipment to use an older version (like 6.0 that Eastkodakguy is using?) to keep my entire plant consistent. Would that be too much to ask my OEMs?

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If you asked us to build a machine with 6.0 on it, we would probably try to convince you other wise. But any version 10 and up (and maybe even 8) we would be happy to use, as long as that version still has all the features we want to use. I dont know about other OEMS though.

2. With CL, is it only the CPU that I have to flash or do other modules require this?

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Yeah, you will have to flash other cards now and then as well. To be honest, I never really know what cards I have to flash until I goto run the machine and I get a revision error in RS Logix


I agree with steve etter, unless you are interested in specific features of control logix, then maybe it isnt the best platform to standardize on

Looking at the compatibility matrix on the Rockwell site shows that the Analog Modules have been at the same minimum revision level since the software was at revision 2.27 (released 10/99)

ControlNet Cards have gone through a few different series but none have required updating since software rev 6.0 and Series D cards haven't needed updating since software revision 2.51 (3/2000).

Ethernet, DH+, and DeviceNet cards all show that the same revisions that worked with software revision 2.51 still work today with revision 11. Same thing for all Analog and Digital I/O modules.

Be aware that a newer revision may be available for some cards but it does not necessarily mean you have to upgrade. An upgrade may be desirable to obtain a new function though.

The CPU is the one that would have to be upgraded if you update your software.

Also be aware that the CLogix is a new platform for Rockwell, meaning new I/O modules, new chassis and new power supplies. However if you already have existing PLC-5 or SLC 500 systems the CLogix has the ability to take over and communicate with this older equipmenet. So someone looking to upgrade doesn't have to scrap their existing system just to use the new one. Keep that in mind when you pick your platform today. 10-15 years from now will you be scrapping what you picked today or adding on to it? I am not familiar with the Omron system so I can't say that they do or do not do the same, just check into it first!

Good luck,

OG