Configuration of the CPU 410
3.3 Status and error displays
CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC
41
3.3
Status and error displays
RUN and STOP LEDs
The RUN and STOP LEDs provide information about the CPU's currently active operating
state.
Table 3- 2
Possible states of the RUN and STOP LEDs
LED
Meaning
RUN
STOP
Lit
Dark
CPU is in RUN state.
Dark
Lit
CPU is in STOP state. The user program is not being executed. Cold restart/restart is
possible.
Flashes
2 Hz
Flashes
2 Hz
The CPU has detected a serious error that is blocking startup. All other LEDs also
flash at 2 Hz.
Flashes
0.5 Hz
Lit
HOLD status has been triggered by a test function.
Flashes
2 Hz
Lit
A cold restart/restart was initiated. The cold restart/warm start may take a minute or
longer, depending on the length of the called OB. If the CPU still does not change to
RUN, there might be an error in the system configuration, for example.
Dark
Flashes
2 Hz
•
A high-quality RAM test (self-test) is executed after POWER ON. The duration of
the self-test is at least 7 minutes.
•
CPU memory reset is active.
Dark
Flashes
0.5 Hz
The CPU requests a memory reset.
Flashes
0.5 Hz
Flashes
0.5 Hz
•
Troubleshooting mode
•
Startup (POWER ON) of a CPU on which a large number of blocks is loaded. If
encrypted blocks are loaded, startup may take a longer time depending on the
number of such blocks.
This display also indicates that internal processes are busy on the CPU and prevent
access to the CPU until completed.
Flashes
0.5 Hz
Flashes
2 Hz
The CPU has downloaded another program and is powering up after power on.
Note that, if necessary, another program and a configuration may be present in the
retentive load memory in the CPU. Ensure that this cannot pose a hazard if the CPU
switches automatically to RUN state. If you have no information about the content of
the load memory, set the CPU to delivery state before powering it up.