Structure of the CPU 410-5H
3.3 Status and error displays
CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB
41
3.3
Status and error displays
RUN and STOP LEDs
The RUN and STOP LEDs provide information about the currently active CPU operating
state.
LED
Meaning
RUN
STOP
Lit
Dark
The CPU is in RUN mode.
Dark
Lit
The CPU is in STOP mode. The user program is not being executed. Cold re-
start/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 self-test
takes at least 15 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.
MSTR, RACK0, and RACK1 LEDs
The three LEDs MSTR, RACK0, and RACK1 provide information about the rack number set
on the CPU and show which CPU controls the switched I/O.
LED
Meaning
MSTR
RACK0
RACK1
Lit
Irrelevant
Irrelevant
CPU controls switched I/O
Irrelevant
Lit
Dark
CPU on rack number 0
Irrelevant
Dark
Lit
CPU on rack number 1