Publication 1762-RM001C-EN-P
Controller Memory and File Types 2-9
Password Protection
MicroLogix controllers have a built-in security system, based on numeric
passwords. Controller passwords consist of up to 10 digits (0-9). Each
controller program may contain two passwords, the Password and the
Master Password.
Passwords restrict access to the controller. The Master Password takes
precedence over the Password. The idea is that all controllers in a project
would have different Passwords, but the same Master Password, allowing
access to all controllers for supervisory or maintenance purposes.
You can establish, change, or delete a password by using the Controller
Properties dialog box. It is not necessary to use passwords, but if used, a
master password is ignored unless a password is also used.
If the Memory Module User Program has the “Load Always” functionality
enabled, and the controller User Program has a password specified, the
controller compares the passwords before transferring the User Program
from the Memory Module to the controller. If the passwords do not match,
the User Program is not transferred and the program mismatch bit is set
(S:5/9).
NOTE
If a password is lost or forgotten, there is no way to
bypass the password to recover the program. The only
option is to clear the controller’s memory.