Siemens SIMATIC S7-1500 System Manual page 115

Behavior of a password-protected CPU during operation
The CPU protection takes effect after the settings are downloaded in the CPU.
Before an online function is executed, the necessary permission is checked and, if
necessary, the user is prompted to enter a password. The functions protected by a password
can only be executed by one programming device/PC at any one time. Another programming
device/PC cannot log on.
Access authorization to the protected data is in effect for the duration of the online
connection, or until the access authorization is manually rescinded with "Online > Delete
access rights".
Access to a password-protected CPU in the RUN mode can be limited locally in the display
so that access with a password is also not possible.
Access level for F-CPUs
For the fail-safe CPUs, there is an additional access level in addition to the four described
access levels. For additional information on this access level, refer to the description of the
fail-safe system SIMATIC Safety Programming and Operating Manual SIMATIC Safety -
Configuring and Programming
(http://support.automation.siemens.com/WW/view/en/54110126).
Automation system
System Manual, 12/2014, A5E03461182-AC
8.2 Configuring access protection for the CPU
Protection
115