Siemens SIMATIC S7-400H - Status and Error LEDs

Installation of a CPU 41x-H
4-8
Automation System S7-400H Fault-tolerant Systems
A5E00068197-07
4.3 Status and Error LEDs
LEDs RUN and STOP
The RUN and STOP LEDs provide information about the currently active CPU
operating status.
LED
Meaning
RUN STOP
H D CPU is in RUN mode.
D H CPU is in STOP mode. The user program is not processed. Restart and
warm restart/reboot is possible. If the STOP status was triggered by an
error, the error indication (INTF or EXTF) is also set.
B
2 Hz
B
2 Hz
CPU has the status DEFECT. The INTF, EXTF and FRCE LEDs also
flash.
B
0.5 Hz
H HALT status has been triggered by a test function.
B
2 Hz
H A warm restart/reboot/restart has been triggered. It can take a minute or
longer to execute the warm restart/reboot/restart depending on the length
of the OB called. If the CPU still does not go into RUN, there might be an
error in the system configuration.
B
2 Hz
B
2 Hz
Self–test running for unbuffered POWER ON.
x B
0.5 Hz
Memory reset is requested by the CPU.
x B
2 Hz
Memory reset is running.
D = LED is dark; H = LED lights up; B = LED flashes with the specified frequency;
x = LED status is irrelevant
LEDs MSTR, RACK0 and RACK1
The three LEDs, MSTR, RACK0 and RACK1, provide information about the
mounting rack number configured in the synchronization module and which CPU
has process control of the switched I/O modules.
LED
Meaning
MSTR RACK0 RACK1
H x x CPU has the process control for the switched I/O
x H D CPU on rack number 0
x D H CPU on rack number 1
D = LED is dark; H = LED lights up; x = LED status is irrelevant