You can choose between three protection levels:
- Protection level 1: corresponds to the default behavior
- Protection level 2: read-only access possible
- Protection level 3: neither read nor write-access possible
You can assign a CPU password within the hardware configuration of your S7 station. Open the Properties dialog box of the CPU there. The protection level 2 (read-only access) and a password assignment are recommended inside the Properties dialog box.
A user who does not know the password can then read the program in the CPU, without entering a password. However, he cannot make changes within the program.
Fig. 1: Setting CPU protection
Block protection (Know_How_Protect) can be assigned for self-created STEP 7 blocks. You can find more information about this under "Block protection (Know_How_Protect) for DBs, FBs and FCs" - entry ID: 10025431.
If you forget your password:
If you forget the password, you do not have write-access (or read-access in level 3) in the password-protected CPU.
To restore access, you have to reset the CPU and reload the program into the CPU.
The password only becomes active once the changed data has been downloaded into the S7-CPU.