Siemens SIMATIC S7-400H Manual page 49

Master CPU (CPU 0)
RUN
Status message "Update" to
all partners logged on
Asynchronous SFCs for data records
given negative acknowledgement
*)
Messages delayed
All OBs up to priority class 15
(inc. 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.
communication delay
OBs of priority classes > 15 are de-
layed with the exception of the time
interrupt OB with special treatment
If appropriate, execution of time
interrupt OB with special treatment
Start of monitoring for max.
blockage time for priority classes > 15
Start of min. I/O hold time
*)
A detailed description of the SFCs, SFBs and communication functions concerned can be
found in the sections below.
Figure 5-2 Process for update
S7-400H Programmable Controller Fault-Tolerant Systems
A5E00068197-04
Update
(REDF LEDs flash at 2 Hz)
*)
Master copies contents of the modified data blocks
*)
Master copies outputs
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 diagnostic buffer
Link-up and Update
Standby CPU (CPU 1)
STOP
5-5