Process For Update - Siemens SIMATIC S7-400H Manual

Master CPU (CPU 0)
RUN
Status message "Synchronize" to
all partners logged on
Asynchronous SFCs for data records
<given negative acknowledgement
Messages delayed
All OBs up to priority class 15 (incl. OB
1) delayed
Start of monitoring for max.<scan-cycle
time extension
Current comm. jobs <delayed or new
ones rejected
Start of monitoring for max. communica-
tion delay
OBs of priority classes > 15 are delayed
with the exception of the watchdog in-
terrupt OB with special treatment
If appropriate, execution of watchdog
interrupt OB with special treatment
Start of monitoring for max. blockage
time for priority classes > 15
Start of min. I/O retention time
Master copies the contents of the data blocks <that have been
modified since they were last copied
Master copies timers, counters, markers,<inputs and the dia-
gnostics buffer
*)
A detailed description of the SFCs, SFBs and communication functions concerned can be
found in the sections below
Figure 6-2

Process for update

Automation System S7-400H Fault-tolerant Systems
A5E00068197-07
Update(REDF LEDs flash at 2 Hz)
*)
Master copies contents of the modified data blocks
Master copies outputs
Linking and Synchronizing
Standby CPU (CPU 1))
STOP
Master role
change
6-5