System modifications during redundant operation
10.3 Adding components
CPU 410-5H Process Automation
160
System Manual, 09/2014, A5E31622160-AB
10.3.5
Step 5: Switch to CPU with modified configuration
Starting situation
The modified hardware configuration is downloaded to the reserve CPU.
Procedure
1.
In SIMATIC Manager, select a CPU of the fault-tolerant system, then choose "PLC >
Operating Mode" from the menu.
2.
In the "Operating Mode" dialog box, click the "Switch to..." button.
In the "Switch" dialog box, select the "with altered configuration" option and click the
"Switch" button.
3.
Acknowledge the prompt for confirmation with "OK".
Result
The reserve CPU connects, is updated (see section Link-up and update (Page 121)) and
becomes the master. The previous master CPU switches to STOP mode, the fault-tolerant
system operates with the new hardware configuration in single mode.
Reaction of the I/O
Type of I/O
One-sided I/O of previ-
ous master CPU
One-sided I/O of new
master CPU
Switched I/O
Added I/O mod-
ules
are not addressed by the
CPU.
are given new parameter settings and updated by
the CPU.
Driver blocks are not yet present. Process or diag-
nostic interrupts are detected, but are not reported.
I/O modules still
present
are no longer addressed
by the CPU.
Output modules output
the configured substitute
or holding values.
are given new parameter
settings
1)
and updated by
the CPU.
continue operation with-
out interruption.
Added DP stations are not addressed by the
CPU.
as for added I/O modules (see above)
1)
The central modules are first reset. Output modules briefly output 0 during this time (instead of the
configured substitute or hold values).
Reaction to monitoring timeout
The update is canceled and no change of master takes place if one of the monitored times
exceeds the configured maximum. The fault-tolerant system remains in single mode with the
previous master CPU and, assuming certain conditions are met, attempts the master
changeover later. For additional information, refer to the section Time monitoring (Page 123).