How the S7-1200 works
4.5 Protecting access to the CPU or code block is easy
Easy Book
Manual, 05/2009, A5E02486774-01
39
4.5
Protecting access to the CPU or code block is easy
The CPU provides 3 levels of security for
restricting access to specific functions. When
you configure the security level and password
for a CPU, you limit the functions and memory
areas that can be accessed without entering a
password.
The password is case sensitive.
You set the security level of the CPU in the
Device configuration. Select the CPU and
expand the properties in the inspector window.
Each level allows certain functions to be accessible without a password. The default
condition for the CPU is to have no restriction and no password-protection. To restrict access
to a CPU, you configure the properties of the CPU and enter the password.
Entering the password over a network does not compromise the password protection for the
CPU. A password-protected CPU allows only one user unrestricted access at a time.
PLC-to-PLC communications (using communication instructions in the code blocks) are not
restricted by the security level in the CPU. HMI functionality is also not restricted. Entering
the correct password provides access to all of the functions.
With password protection, you can use instructions for process control and communications
without restrictions. For example: To modify the tags in a CPU that was configured for
read/write protection, you must enter the configured password because this function requires
write access.
Security level
Access restrictions
No protection
Allows full access without password-protection.
Write protection
Allows read-only access to the CPU, HMI access, and PLC-to-PLC
communications without password-protection.
Password is required for modifying (writing to) the CPU and for
changing the CPU mode (RUN/STOP).
Read/write protection
Allows HMI access and all forms of PLC-to-PLC communications
without password-protection.
Password is required for reading the data in the CPU, for modifying
(writing to) the CPU, and for changing the CPU mode (RUN/STOP).