Siemens SIMATIC ET 200AL, System Manual

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Communications services
3.6 Secure Communication
Communication
98
Function Manual, 05/2021, A5E03735815-AJ
When a project is loaded into the CPU, the CPU receives the project data:
•
Hardware configuration including configured certificates for secure communication
(OPC UA, HTTPS, Secure OUC, Secure PG/HMI Communication)
• User program
Figure 3-34 Connection establishment, provisioning phase
Ending the provisioning phase
TIA Portal does not store the password for confidential PLC configuration data itself or the key
information generated from the password in the project.
Therefore, the password is requested in a dialog when loading the project for the first time or
when loading a new project and transferred to the CPU as key information. Only after this
step the CPU is able to use the protected PLC configuration data - this completes the
provisioning phase and the CPU can start operating.
If you do not protect the confidential PLC configuration data with a password, there is no
need to enter the password when loading the CPU for the first time. This has no influence on
the flow of the PG/HMI communication but you have to consider that the confidential PLC
configuration data (e.g. private keys) offer almost no protection against unauthorized access
in this case.