Siemens SIMATIC S7-1500 Function Manual page 110

Device view of the system
In the device view, you see the operating states of the CPUs based on the icons above
PLC_1:
● Green icon: PLC_1 is in the RUN operating state.
● Yellow icon (wrench) for maintenance demanded: PLC_2 is in the STOP operating state.
PLC_2 indicates that the online connection is available through the partner (PLC_1).
You can find more detailed information on the system faults in the "Diagnostics" tab, in
"Device information". The device information indicates maintenance demanded and RUN
operating state for PLC_1.
Figure 7-8 Diagnostics example: Device view of redundant system (RUN-Solo)
Diagnostics
Function Manual, 11/2019, A5E03735838-AF
7.3 Diagnostics view in the project tree and in the device view and network view
Diagnostics of the S7-1500R/H redundant system
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