Siemens S7-1500 - Meaning of the RUN;STOP, ERROR and MAINT Leds

Interrupts, error messages, diagnostics and system alarms
4.1 Status and error display of the CPU
CPU 1511T-1 PN (6ES7511-1TK01-0AB0)
30 Manual, 09/2016, A5E36270833-AA
Meaning of the RUN/STOP, ERROR and MAINT LEDs
The CPU 1511T-1 PN has three LEDs to signal the current operating status and diagnostics
status. The following table shows the meaning of the various combinations of colors for the
RUN/STOP, ERROR and MAINT LEDs.
Table 4- 1 Meaning of the LEDs
RUN/STOP LED
ERROR LED
MAINT LED
Meaning
LED off
LED off
LED off
Missing or insufficient power supply on the CPU.
LED off
LED flashes red
LED off
An error has occurred.
LED lit green
LED off
LED off
CPU is in RUN mode.
LED lit green
LED flashes red
LED off
A diagnostics event is pending.
LED lit green LED off LED lit yellow
Maintenance demanded for the plant.
The affected hardware must be checked/replaced
within a short period of time.
Active Force job
PROFIenergy pause
LED lit green LED off
LED flashes yellow
Maintenance required for the plant.
The affected hardware must be checked/replaced
within a foreseeable period of time.
Bad configuration
LED lit yellow LED off
LED flashes yellow
Firmware update successfully completed.
LED lit yellow
LED off
LED off
CPU is in STOP mode.
LED lit yellow
LED flashes red LED flashes yellow
The program on the SIMATIC memory card is
causing an error.
CPU defective
LED flashes yellow
LED off LED off
CPU is performing internal activities during STOP,
e.g. startup after STOP.
Download of the user program from the SIMATIC
memory card
LED flashes
yellow/green
LED off LED off
Startup (transition from RUN → STOP)
LED flashes
yellow/green
LED flashes red LED flashes yellow
Startup (CPU booting)
Test of LEDs during startup, inserting a module.
LED flashing test