Using Secure Hmi Communication - Siemens SIMATIC ET 200AL System Manual

Startup of PG/HMI communication
When the CPU is loaded and has received the CPU certificate for Secure PG/HMI
Communication, the programming device connects again - this time based on the loaded
CA certificate.
Figure 3-35
3.6.4.5

Using secure HMI communication

As of TIA Portal version V17, the CPU and the HMI device communicate via secure HMI
communication if both devices meet the requirements for this type of communication.
The basis of secure HMI communication is that the HMI device can verify the authenticity of
the CPU, using the PLC communication certificate that the CPU sends when establishing
communication, and considers the CPU to be "trustworthy". Secure HMI communication is
only possible when this turns out to be the case.
This section describes the measures you must take for the various HMI devices to manually
label the PLC communication certificate as "trustworthy".
Requirement
• CPU and HMI device support secure HMI communication.
• A current project is available on the CPU (TIA Portal V17 and higher).
Communication
Function Manual, 05/2021, A5E03735815-AJ
Startup of PG/HMI communication
Communications services
3.6 Secure Communication
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