S7-400H
System Manual, 03/2012, A5E00267695-11
281
System modifications during operation
17
17.1
System modifications during operation
In addition to the options of hot swapping failed components as described in section Failure
and replacement of components during operation (Page 265),
you can also make changes to the system in a fault-tolerant system without interrupting the
running program.
The procedure partially depends on whether you are working with your user software in PCS
7 or STEP 7.
The procedures described below for changes during operation are
designed so that you start with the redundant system mode (see section The system states
of the S7-400H (Page 124)) with the aim of returning to this mode when the procedures are
completed.
NOTICE
Keep strictly to the rules described in this section with regard to modifications of the system
in runtime. If you contravene one or more rules, the response of the fault-tolerant system
can result in its availability being restricted or even failure of the entire automation system.
Only perform a system change in runtime when there is no redundancy error, i.e. when the
REDF LED is not lit. The automation system may otherwise fail.
The cause of a redundancy error is listed in the diagnostic buffer.
Safety-related components are not taken into account in this description. For more
information on dealing with fail-safe systems refer to the
S7-400F and S7-400FH Automation
Systems manual.
