slc 500 newbie question 3

[2Tricky]

Hello. This is my first proper investigation into the prognosis for our circa 1995 Allen Bradley slc 500. It is part of a printing press and due to the manufacturer having closed there is no 'horses mouth' route for us to amend the turnkey program.

As a hobby programmer with many languages under my belt I am interested in learning ladder logic and want to personally tweak the program if a all possible. Ironically I haven't got a clue as to whether this is like falling off a log or otherwise and am worried about any password protection in place if indeed passwords are used. I understand that there is an AB emulator around that I might be able to use in principle but given that I don't even know what processor is being used this too is a big question mark.

If anyone can help me to get my hands dirty I would be very grateful - many thanks.

 

[controlsdude]

slc500
data table type processor, all variables tied to a data location.
RSlogix500 is needed for the programming package
RSlinx is needed as a bridge between your laptop and RSlogix500
If you go to the AB website, just download everthing from hardware and software user manuals on slc500. Read it, then you will be asking particular questions instead of the generlaties above.

Also, call your local distributor for ab, they usually can set up a lunch and learn about RSlogix500. Visit the distributor and try to pick the techinal rep's brain for ab there about basics. They usually dont charge for this but who knows nowadays.

 

[danw2]

I can understand your concern about password protected program.

If the SLC program is locked, what good is you investing in software? I don't know what A-B's policy is on getting past password protection, whether they have some procedure for it. Maybe others here do know and can comment.

It might pay to hire an integrator who already has the software to try to download the PLC program to see if it's open and available, before you invest in software.

Or consider hiring an integrator to do what they're skilled at but will be a learning curve for you.

How big are the changes you need made?

 

[FredSanford]

BTW you can 'sniff' the password out with a serial tap to a second PC.
RSLogix has to ask the PLC what the password is so it can compare
it too the password that you type in..

This works on several PLC brands and software..

http://carolinaboardrepair.com

Vintage PLC Repair

 

[2Tricky]

Thanks all, I know it takes effort to respond and I appreciate it.

My usual approach is to take the route of least resistance and there is quite a lot of resistance against spending anything. As a keen tinkerer I view almost anything new (in programming) with interest - providing that there is a glimmer of hope that I can be useful.

For me the sky (or imagination) is the limit but at the moment we specifically want to tweak the machine to automatically register colour to colour and/or colour to cutter/s. The machine appears to have the necessary board/s already and needs optics hooking up and then presumably the odd flag etc being set in the main program. I certainly want to limit the scope of my experimentation because of the serious impact it could have on the machine.

FredSanford I'm intrigued by this sniffing of which you speak and wonder if you can offer any more guidance please.

Many thanks again.

 

[FredSanford]

It took me a while to find the link again..
I have a paper copy of this at the shop..
We don't come across this problem very often, but its nice to
know that you can do this.
We have ran across dead backup batteries in PLCs where the OEM is long
gone and the customer has no backup of the machine software.

http://carolinaboardrepair.com

Vintage PLC Repair

 

[controlsdude]

on slc500 and ab plc5 the password bypass backdoor was ABUNLOCK, if you view you phone those are the number you use. RSlogix5000 is different, probably like the above suggestion.

 

[2Tricky]

Perhaps I'm getting ahead of myself but it looks like getting into the system is licked - thanks chaps.

I sense that it is a case of slowly slowly catchy monkey but I trust (or at least hope) it is not as bad as learning to use Windbg to debug in MS Windows...

Controlsdude, sounds like I should take a look at the software you mention - I have looked at the manual and from memory it is rather cryptic but it is funny how as ones project context becomes clearer, some things begin to focus.

Thanks again.