Programming SLC550


Thread Starter

Peter Bubik

A project was dumped on me:
There is an Allen-Bradley SLC550, no one has the a backup of the program (there is a copy running on the SLC), I need to learn about the program and how to modify it (just add a couple of lines and expand the SLC: add couple Thermocouple modules, and a Modbus Card)

I was told that Allen-Bradley have all their hardware programmable only with their own software (RSLogix???) that one can purchase for a modest ransom of $5000.

Is there any other way for me to connect to the SLC and see what is running there and modify it? I don't mind paying a few hundred - but $5000 is
ridiculous - considering that I only need to modify two or three lines.

What are my options here?
Where in the world does RSLogix500 cost $5000? I just bought a copy of the standard version for $1100 (part number 9324-RL0300ENE).

It sounds like you need to do more than just change a few lines. If you are adding additional I/O cards, the memory for those inputs and outputs needs to be allocated as well restructuring the processor's memory. Also, I am guessing that a Modbus card may require some block transfers. Uless your SLC has a relatively new version of the firmware, block transfer instructions will not be available and you will have many many rungs to add. It sounds to me like the $1100 would be well worth the price.

Something else to consider: Without the original project file, all you will be able to upload from the processor is raw logic. You will not get the rung comments, address descriptions, or any other helpful text that should have been added to the project file. It does not make learning and changing the logic impossible, just more difficult. Having the full functionality of RSLogix500 will help in that effort.

Good Luck!

And the "Starter" version of RSLogix 500 that lacks many of the online editing features costs $500.

Because you've never worked on an SLC-500 before, and it sounds like you won't work on it again after you modify this one, it might make more sense to hire somebody's time who already knows the SLC-500 language and configuration intimately. Most "systems integrator" shops, especially in the USA, have A-B experience and equipment.
Another couple of things to consider - by SLC550 I presume you mean 500, or is it 5/05? - There's a number of diferent interfaces available. The older 5/01 & 5/02 modeuls require a "PIC" module, but the 5/03, 5/04 and 5/05 can be programmed with a standard AB serial lead. You need to be familiar with their comms program (RSLinx) to get set up, but it's not that difficult.

There are a couple of options for the Modbus card, SST and Prosoft. I'd suggest you get hold of the manuals from their websites at or before you start.

happy hunting
There was at one time, a dos based programming software called APS from Allen-Bradley. It ran tandem to the 6200 software supplied by Allen-Bradley, but I'm not sure if you can still buy it or not. The current programming software from Allen-Bradley is RSLogix 500, and it is the only other option. The other thing you might do is see if you can find the Allen-Bradley distributor in your area, and see if they have an Applications Engineer on staff, and he might be able to help. Unfortunately to my knowledge, no one else sells a programming and communication package for Allen-Braldey SLC's.

Bob Peterson

Its more like $1000 then $5000.

Spend the bux and do it right.

Alternately you could maybe pay an integrator to do it for you.

Bob Peterson

James Bouchard

The $5000 figure includes both on line and off line programming. You could get just the on line one for less ( about =BD ) Still a lot for a couple lines. Even the third party programming software is expensive so I don't thing you will be able to get away for much less. Best bet would be to find a integrator who has the software and pay them to do it. I don't see how you are going to add several analog modules etc and only add a couple lines of programming. It sounds like the project will be bigger than just a few lines.

The model number looks wrong since the SLC's are either SLC 500 ( fixed rack ) or 5/01 to 5/05 I do not recall a SLC 550 model number and a check
of their site does not show one either. There is a display called the panel view 550 but that is a different thing all together

James Bouchard

Larry Lawver


I can understand charging you $5000 because of your attitude, but you can probably use the RSLogix500 Starter Package, 9324-RL0100ENE, $499. By the way, the top of the line package for SLC500 programming is $1100 and worth every dime. There are no longer any third party programming packages available, as far as I know.

There is no Allen-Bradley SLC550; I'm guessing you have a SLC 5/05. The programming task you describe is not trivial for someone who is clearly not even slightly familiar with the controller, and I suggest you seek assistance from the OEM who built the machine and/or your local Rockwell Automation distributor. This would have been a better approach in the first place, rather than posting your lack of clues to a list.

Hope this helps!

Larry Lawver
Rexel / Central Florida
Dangit, James, cut that out.

No SLC-500 ladder editor program sells for Five Thousand United States Dollars. Nowhere. Not Ever.

sujit kumar sarkar

Dear Peter

without Rs linx & rs logix 500 you cant communicate easily with SLC. if you are in trouble please send the ladder soft copy to my email address & what change you required. i will do it & send you back.

i am working in Rockwell System integrator.


[email protected]

Ranjan Acharya

It is Rockwell / A-B's PLC, why shouldn't they make some brass on selling the software for it too? The money paid through one-time or annual fees obviously has to help out their shareholders - that's called capitalism by the way. But the rest of it funds their engineering staff, support staff, manufacturing staff, office staff and so on. Normal people like you and me with mortgages and clogged arteries.

You have to make money - part of capitalism too -- to put bread on the table. Some of the smaller Linux guys do it by charging US$50 an your or equivalent. The larger manufacturers do it by selling standardised packages for US$1500 with one year of technical support (or something like that).

I don't think such comments are fair to Rockwell. We support them and Siemens and Modicon and a bunch of other automation vendors. They all (that capitalism thing again) charge for their hardware and software. I have yet to find one that provides real support for free products - even Linux has a pied piper that has to be paid. "Playing a tune on a flute is not worth 1000 florins. Get out of Hameln".

Sure, Rockwell needs to make money. But they also have to be competitive. That is why Automation Direct is kicking their butts in the marketplace. Why should one get an AB at a $6 to 7 thousand difference for the equivalent PLC and then have to fork over $1100 for the ladder program and another $3300 for the PID tuning software. Automation Direct offers full function equivalent of the two programs for a little under $500.