TechTalk : RSLogix 500 – How-To Unlock PLC LogicI have been in situations where I am taken over a role of a resident PLC programmer who have left the organization. And he/she has locked the PLC logic (lets say for security reasons). To make the situation worst, has not left any traces of documents and directions on how to unlock it. Enough of my ranting.

This is how you unlock SLC500 PLC logic.

Open the PLC logic by double clicking the SLC500 PLC logic file (see image below).

Xybernetics RSLogix 500 : How-To Unlock PLC Logic

When you are prompted to enter a password/master password, enter “ABUNLOCK” as a password.

Xybernetics RSLogix 500 : How-To Unlock PLC Logic

Another way to unlock the PLC logic is to enter the following sequence of numbers,


Here are some key notes.

  • The password (ABUNLOCK) is in all upper case and no spaces (and no double quote).
  • This password has been tested to work for SLC500 (Version 9.00.00 (CPR 9)


Last Notes
Note that RSLogix 5000 (for ControlLogix) has a different method to edit/copy protect the logic via a tool called Source Protection Software where
it utilizes “key file” (aka “sk.dat”) to lock the logic down. More on this can be found in my TechTalk link called Unlock RSLogix 5000 Logic