Siemens S5-135U/155U - Manual (Page 275)

6-13
System Manual
C79000-G8576-C199-06
6.3 Coordinator Modes
If, when the supply voltage is switched on, the coordinator mode switch is at
STOP or another stop request is pending, the CPUs remain in the Stop state.
AUTOMATIC RESET or
AUTOMATIC RESTART
If, when the supply voltage is switched on, the coordinator mode switch is at
RUN, an AUTOMATIC RESET or AUTOMATIC RESTART (depending on
DX 0 setting) will take place as long as the mode switches of the CPUs are
also at RUN and the PLC was previously in cyclic operation.
MANUAL START
When you set the coordinator mode switch from STOP to RUN, the CPUs
will execute a start if this was already prepared at all CPUs by appropriate
switch actuation, i.e. the CPUs are in the wait state. As required by the user,
the type of start can be the same for all CPUs or arbitrarily different.
After the start synchronization by the system programs, the CPUs
simultaneously go to RUN (cyclic operation).
The transition of individual CPUs is synchronized - as long as the preset
“start synchronization” in the relevant CPUs has not been changed by DX 0
programming - i.e. only when each CPU has ended its start do all CPUs
jointly go to cyclic program processing.
If the coordinator mode switch is at the RUN setting and one CPU goes to
the Stop state, all the other CPUs also go to the Stop state. The red STOP
LED(s) on the CPU(s) causing the Stop state flash slowly; the STOP LEDs of
the other CPUs are continuously lit.
Apart from any indication with fault LEDs on the CPU which is the cause, all
CPUs emit the BASP (output inhibit) signal.
The Stop State
Startup
Normal Operation
and Stop in the
Event of Faults
Multiprocessor Operation/Coordinators