Plant changes during redundant operation - H-CiR
12.6 Motivation for H-CiR via PROFIBUS DP
CPU 410 Process Automation/CPU 410 SMART
204 System Manual, 05/2017, A5E31622160-AC
Motivation for H-CiR via PROFIBUS DP
In addition to the options described in Replacement of failed components during redundant
operation (Page 223) for replacing failed components in RUN, you can also make plant
changes with CPU 410 in redundant mode without interrupting the program that is running.
The procedure and scope depend on the operating mode of the CPU.
The procedures described below for making changes during operation are each created in
such a way that they start from the redundant system state (see Chapter The system states
of the fault-tolerant system (Page 109)) and have as their objective a return to redundant
system state.
Note
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 plant change in runtime if there is no redundancy error, i.e. if the REDF
LED
n system may otherwise fail.
The cause of a redundancy error is listed in the diagnostics buffer.
Safety-related components are not taken into account in this description. For more
information on handling fail-safe systems refer to the
S7 F/FH Systems - Configuring and
Programming
manual.
For switched I/O to be expanded during operation, the following points must be taken into
account already at the system planning stage:
● In both cables of a redundant DP master system, sufficient numbers of branching points
are to be provided for spur lines or isolating points (spur lines are not permitted for
transmission rates of 12 Mbit/s). These branching points can be spaced or implemented
at any points that can be accessed easily.
● Both cables must be uniquely identified so that the line which is currently active is not
accidentally cut off. This identification should be visible not only at the end points of a
line, but also at each possible new connection point. Different colored cables are
especially suitable for this.
● Modular DP slave stations (ET 200M), DP/PA links and Y links must always be installed
with an active backplane bus and fitted with all the bus modules required wherever
possible, because the bus modules cannot be installed and removed during operation.
● The configuration of the terminal modules with the ET200iSP should have sufficient
reserves and be fitted with unconfigured standby modules.
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