Siemens S5-135U/155U System Manual page 77

Startup and
The following flowchart provides an overview of the sequence for startup
Validity Check
and validity check of a CC with CPU inserted and with no user program. For
the CPU 948, all steps relating to the memory submodule are skipped.
Insert memory submodule in
CPU (not with the CPU 948)
CPU at "STOP"
Connect power supply unit
Switch on supply voltage
PS:
LED "DC5V"
No
and "DC 24V" on, all
others off
Yes
CPU:
No LED "BASP" on
LED "STOP" flashing fast
all others off
Yes
CPU general reset
CPU:
LED "STOP" on
No
LED "BASP" on LED "STOP" flashing fast
all others off
Yes
Reset CPU: Set to "Reset,"
switch from "STOP" to "RUN"
CPU: Replace memory submodule
No
LED "RUN" on,
LED "BASP" off
Yes
Unit O.K.
Figure 4-5 Startup
System Manual
C79000-G8576-C199-06
Central Controllers and Expansion Units Power Supply Units
PS:
No
Correctly wired?
Voltage Present?
Yes
Yes
No
LED "RB Press
RESET
Low" on
LED off
Yes
No
Press
LED "MB
Check backup bty
RESET
Low" on
LED off
LED "Fan
Fault" on
LED
"Voltage
Low" on
CPU:
No
LED "BASP" on
all others
off
Yes
Memory
No
Insert memory
submodule:
submodule correctly
correctly inserted?
Yes
Replace bty
compartment
Replace
rechargeable
battery
Yes
No
Fault
corrected
and replace
if necessary
Check
Fan
Fault
corrected
Check load
voltage
connection
Replace CPU
or
repeat startup
Yes
No
Replace PS
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