I have tried to access an AB SLC 5/01 plc, but the “Deny Future Access” bit is set to 1. The owner of the machine has tried to contact the manufacturer for a copy of the program, but the manufacturer has gone out of business.
When I log onto the PLC I get “This program has been PROTECTED from user access!” I have search for all instances of S:1/14, but it is not in logic. I have contacted an Allen Bradley representative but to no avail.
I set up an AB plc which I have at home, and turned on S: 1/14 and downloaded the program to the plc. There is no logic in the plc that sets or resets S: 1/14. I cannot toggle the bit to 0.
Does someone know of a way to turn off S: 1/14 in order to access the logic?

 

AB can do this, but for obvious reasons they want to be sure you have a valid reason and will indemnify them of any legal issues. If your vendor is out of business, and you can get a company officer to take responsibility I believe you can send the unit in and have the protection removed. If you simply want to work around somebodies IP protection, you're probably out of luck. Don't get me wrong, I think you should resolve this issue up front and either refuse acceptance of any machine with this protection applied or live with the consequences. For the small machines I've encountered where you can't get what you need from the vendor, I usually simply re implement with the hardware I like and write them off the approved vendors list. The last project I did was where the vendor wanted $7000 and a month or two to come and replace an obsolete display with a current Maple Systems unit which would still leave us with an obsolete Omron PLC. I couldn't get what I needed to do the job, so in a few days it had a Maple display and a Micrologix PLC and we can fix it immediately if there is ever another problem. I had the Micrologix in stock or it probably would have an AD (Koyo) or Mitsubishi FX just for the experience. IMHO, this is a far better solution to the problem as equipment with secrets is simply unmaintainable within our uptime requirements. But this should never happen, it's negligent to let it happen, maintainability should be a big part of the purchasing decision.

Regards
cww

 

If you want, and if you can shut the process down, you can send the processor - and the rss file if you have it - to us and we'll clear the bit for you.

You can email me as michaelb at ind-info.com if you need details.

Michael