Link-Up And Update; Effects Of Link-Up And Updating; Table 9-1 Properties Of Link-Up And Update Functions - Siemens SIMATIC S7-400H System Manual

Link-up and update

9.1

Effects of link-up and updating

Link-up and updating are indicated by the REDF LEDs on the two CPUs. During link-up,
the LEDs flash at a frequency of 0.5 Hz, and when updating at a frequency of 2 Hz.
Link-up and update have various effects on user program execution and on communication
functions.
Table 9-1
Process
Execution of the user
program
Deletion, loading,
generating and
compressing blocks
Execution of communication
functions, PG operation
CPU self-test
Test and commissioning
functions, such as "Monitor
and Control Tag", "Monitor
(On/Off)"
Handling of the connections
to the master CPU
Handling of the connections
to the standby CPU
S7-400H
System Manual, 09/2007, A5E00267695-03
Properties of link-up and update functions
Link-up
All priority classes (OBs) are
processed.
Blocks can not be deleted,
loaded, created or compressed.
When such actions are busy,
link-up and updating are
inhibited.
Communication functions are
executed.
Not performed
Test and commissioning
functions are disabled.
When such actions are busy,
link-up and update operations
are inhibited.
All connections are retained;
no new connections can be
made.
All the connections are
cancelled; no new connections
can be made.
Update
Processing of the priority classes is
delayed section by section. All the
requirements are caught up with after
the update.
For details, refer to the sections below.
Blocks can not be deleted, loaded,
created or compressed.
Execution of the functions is
restricted section by section and
delayed. All the delayed functions are
caught up with after the update.
For details, refer to the sections below.
Not performed
Test and commissioning functions
are disabled.
All connections are retained; no new
connections can be made.
Aborted connections are not restored
until the update is completed
All connections are already down.
They were cancelled during link-up.
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