AB ControlLogix vs SLC?

Hi,

I work for OEM that has been using AB SLC 5/05 processors to control the machines we build for several years. They work fine, we own the RsLogix 500 software, and we know how to program them.

Recently, it seems that some of our customers have been requesting a ControlLogix PLC. Looking quickly at the AB website, I had a hard finding a direct comparison between the SLC's and the ControlLogix processors. If anyone who has used both types of PLC's could tell me some of the advantages/disadvantages ControlLogix has over the SLC's, I would really appreciate it.

Thanks,
Paul

you could ave searched for comparison in this forum. this was discussed many times.

CLX is much more powerfull system (faster, more memory, more features, allows multiple CPUs, user data types, supports more network types, motion, more math etc.). It is definitelly interesting system for larger project or if you do motion, networking etc.

Programming enviroment is different and although platform is more powerfull, your milage may vary but I find it takes longer than on SLC to do smaller to medium size project projects but this changes as the project size increases.

Tag names are downloaded to CPU but this is still not going to help you much if you loose file and all comments but it's better than nothing...

CPU come only with one RS232 port. To get it on Ethernet you have to buy extra card. CPUs come with cut-down version of firmware that need to be replaced when you receive it. If you are stuck with DF1 to do it, get donuts, lot's of coffe and something to read.

RSLogix5000 is quite stable after all struggle it went through.
You still have to match revision level of software and PLC you are working on. This is pain but at least you can have couple of versions installed and the time of huge files is over (they used to be sized like movie files).

If you have to use older AB HMIs (PV standard for example) or 3rd party screens, you will have to do some mapping. If you go for PV_Plus for example you won't have to do this but you will have to invest in another software package. It can do more but it costs more and it has more apetite for your PCs resources. It is not nearly as stable as PanelBuilder32 but Rockwell is working on it and it will be in better shape now than it was yesterday. I didn't need to use it for almost a year now so others will know better.

I have used both.

We now only use ControlLogix processors (or Micrologix processors when we need a brick.) We have not done anything new with SLC500s for about four years.

The CLX processors are far more powerful that the SLC500 processors. The programming is entirely tag based. They support an expanded instruction set, multiple programming languages, and user defined data types, enabling object oriented programming. Code is much easier to re-use. Parameters may be passed to subroutines. The entire tag database, including tag names and tag comments are downloaded into the PLC (instead of residing on the hard disk as with the SLC500 and most other PLCs, so someone attaching and uploading directly from the PLC also gets the documentation.



The low end CLX processors are cost competitive with the SLC 5/05. IO is about the same, but the IO family for the CLX is more extensive.

You might want to look at the compact-logix. The compact logix is limited to 16 IO modules but if it can meet your needs then you will have a superior PLC based on the Logix-5000 instruction set for half the cost of a SLC-500.

You really need to talk to your distributor and get the scoop from him as he can sit down and show you all the features and advantages.

Expect this request to grow. We just purchased 3 entire packing lines and requested the same thing.

Control logix processors are more powerful, faster and a lot more flexible. Most people are probably requesting them simply to stanadardize on one product. This processor was made to replace the PLC-5 but is economical enough to fill the spot of a SLC. Although a compactlogix would work as well and is still more flexible than the SLC. The hardest learning curve in the control logix is the tag structure. Once learned I think you will like it. The flexibility allows you to put multiple processors or communications cards in one chassis. I would stay away from control net though and go ethernet IP for I/O.

All this may be overkill for your machine but it allows your customer to stock one type of processor and I/O modules as well as giving them future flexibility. They also only have to use one software package.

Most equipment vendors we ran into supplied the CLX as a cost upper. An alternative would be to convert to compactlogix with the control logix as a cost upper (they both use the same programming software). Your conversion is inevetible since compactlogix and control logix will out live the SLC.

You will probably get better info from your distributor though or from the AB automation fair.

** sorry for double info there were no replies when I started typing

KCDAVE

I would stay away from control net though and go ethernet IP for I/O.

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Beware this advice... If you need data to be at the processor at a specific time everytime for your I/O; Ethernet will NOT do it for you. The 100mb label is misleading. ControlNet is made for I/O. Ethernet is not. EtherNet is for Panelviews and data collection. ControlNet is not. ControlNet has a specific Network Update Time that is the same everytime (perfect for I/O). EtherNet is fast, but not repeatable as far as Update Times are concerned (perfect for data collection). Just food for thought.

sportster said:

KCDAVE Beware this advice... If you need data to be at the processor at a specific time everytime for your I/O; Ethernet will NOT do it for you. The 100mb label is misleading. ControlNet is made for I/O. Ethernet is not. EtherNet is for Panelviews and data collection. ControlNet is not. ControlNet has a specific Network Update Time that is the same everytime (perfect for I/O). EtherNet is fast, but not repeatable as far as Update Times are concerned (perfect for data collection). Just food for thought.

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Agreed. Ethernet is not determinisic, Controlnet is and has the additional capability of redundancy.

I think that first we need to differentiate between repeatable and predicitable. Should you follow the directions AB recommends and use managed switches, you can make Ethernet IO extreemly predictable. Controlnet can be configured to guarantee that a particular piece of data arrives every 25ms for example. You'll have your data ontime, not late, but also not early. Ethernet IO can also be configured to deliver your data on time (with a managed swtich) such that your data is never more than 25mS old, it might however be less than 25mS old. But the network performance is predictable.
99.9% of applications will do just fine under those conditions.

I have avoided usine ethernet IO for the most part for other reasons such as those I stated in another thread, http://www.plctalk.net/qanda/showthread.php?t=16191 however we should give as accurate information as we can.

A lot of people will tell you they have a hard time with the control logix..They will point out the major flaws..Like firmware updates..(Modicon users who have lost there firmware will tell you the download time is about the same)..I just finished my first project with it and it was FUN!!..A Major learning curve for me.( i was trained on AB100's and then went to Modicon 984...) They will also tell you of all the bad things about PV+ and RSview ME.. Yes i had a hard time with setting up communications..but maybee becouse i wasnt rea familar with RS linx lite i figured it out (with a couple of questions posted here and there) in about 2 or 3 hours..(Remeber i have had no training on any of these products)..After about 2 weeks i had a working model of machine that was being rebuilt..I had the time so i played around and made it better and the project ( a very tight time line) went with out a hiccup and is still going strong now..(I have made some Tweeks in the last couple of months but nothing major)..

All in all i found the control logix to be nice to set up..Fast and powerfull..

Now i know i didnt get into communications much wityh the last project but i did have 1 remote rack and a PV+..It was fairly straight forward to get it all to work..

would i recomend it..Hell yes!..The tag based programing is a dream..( If you are used to B7:0,0 the it might take a while to rethink your train of thought..but to me..Master_stop..is easier to remember that O:0:1.1)

But hell i am just a CL rookie...

However i cant wait for the next project..It should come up in about 3 months or so and this one involves 6 axis of motion!!

D

My impression is that if you are replacing SLCs with a new A-B platform then the CompactLogix is the way to go. I think of the ControlLogix as a very top end kind of system.

We are getting ready to port our first project from SLC to CompactLogix. I haven't got into heavy programming yet, but the first try at it looked pretty good. My only gripe so far is that I may have to give up my keyboard fixation and rely more on that darned mouse.

I have two applications working fine with Ethernet connection between chassis using an unmanaged Hirschman Spider as a switch.

My applications would typically be controlled by a DCS running at 1 second scan time so 100MB/s with a switch for preventing collisions is way faster.

seriously... unless your ethernet network is completely mismanaged, antiquated, or overloaded it should be fine.

we've got some pretty awful collision domains in our building and i still rarely see a ping go over 15ms unless faulty equipment is involved. But i guess i do need to mention that my machines are all on dedicated ports on managed switches.

Tom Jenkins said:

My impression is that if you are replacing SLCs with a new A-B platform then the CompactLogix is the way to go. I think of the ControlLogix as a very top end kind of system.

We are getting ready to port our first project from SLC to CompactLogix. I haven't got into heavy programming yet, but the first try at it looked pretty good. My only gripe so far is that I may have to give up my keyboard fixation and rely more on that darned mouse.

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We are switching over to Control Logix slowly, and I am using parameters and AOIs. 80% of my code is completed before I start.

Advantages/disadvantages:

ControlLogix/CompactLogix = Future
SLC = Past

Simple as that I am afraid. The Logix platform is a great platform, but one that you need to be educated on to create "structured" program. I say that because the use of tags in a logic can become sloppy and if the programmer doesn't understand how to structure the program customers can be left with a sour taste. The sooner you can get your business exposed and pushing this line the better your future viability will be.

Hopefully he did. This is a six year old thread! If he did transition to Compact/ControlLogix, it would be interesting to hear about his experiences.

jkerekes said:

Hopefully he did. This is a six year old thread! If he did transition to Compact/ControlLogix, it would be interesting to hear about his experiences.

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hahahahahah, I usually check for that....