Siemens SIMATIC S7-1500R/H Manual page 32

Meaning of the RUN/STOP, ERROR and MAINT LEDs
CPU 1517H-3 PN has the following LEDs for displaying the current operating state and
diagnostics status.
Note
LED patterns of the S7-1500H redundant system
Note that it is not always possible to:
• Determine the state of the CPU from the signal pattern of individual LEDs
• Determine the state of the other CPU from the signal pattern of a CPU
The "Meaning" column only shows a possible typical cause.
To investigate the cause of the signal pattern, use the diagnostic buffer and its display via:
• STEP 7
• HMI devices
• Displays of the CPUs
CPU 1517H-3 PN (6ES7517-3HP00-0AB0)
Equipment Manual, 11/2019, A5E42011886-AB
Interrupts, diagnostics, error messages and system events
4.1 Status and error display of the CPU
31