Siemens CPU 1518-4 PN/DP ODK Manual page 34

Interrupts, error messages, diagnostics and system alarms
4.1 Status and error display of the CPU
Meaning of the RUN/STOP, ERROR and MAINT LEDs
The CPU 1518-4 PN/DP ODK 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
RUN/STOP LED
LED lit green
LED lit green
LED lit green
LED lit green
LED lit yellow
LED lit yellow
LED lit yellow
LED flashes yel-
LED flashes
yellow/green
LED flashes
yellow/green
34
Meaning of the LEDs
ERROR LED
LED off LED off
LED off
LED flashes red
LED off
LED flashes red
LED off
LED off
LED off
LED off
LED flashes red
LED off
low
LED off
LED flashes red
MAINT LED
Missing or insufficient power supply on
the CPU.
LED off
An error has occurred.
LED off
CPU is in RUN mode.
LED off
A diagnostics event is pending.
LED off
Maintenance demanded for the plant.
LED lit yellow The affected hardware must be
checked/replaced within a short period of
time.
Active Force job
PROFIenergy pause
Maintenance required for the plant.
The affected hardware must be
LED flashes yel-
checked/replaced within a foreseeable
low
period of time.
Bad configuration
Firmware update successfully complet-
ed.
LED flashes yel-
low
CPU is in STOP mode.
LED off
The program on the SIMATIC memory
card is causing an error.
LED flashes yel-
CPU defective
low
CPU is performing internal activities
during STOP, e.g. startup after STOP.
LED off
Download of the user program from the
SIMATIC memory card
Startup (transition from RUN → STOP)
LED off
Startup (CPU booting)
Test of LEDs during startup, inserting a
LED flashes yel-
module.
low
LED flashing test
CPU 1518-4 PN/DP ODK (6ES7518-4AP00-3AB0)
Meaning
Manual, 09/2016, A5E35681108-AA