Siemens SIMATIC S7-400H System Manual page 246

System modifications in operation
14.9 Reconfiguration of a module
Reaction of the I/O
Type of I/O
I/O modules
Central modules are first reset. Output modules briefly output 0 during this time (instead of the configured substitute or
1)
hold values).
Reaction to monitoring timeout
The update is aborted 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 further information, refer to section Time monitoring (Page 106).
Where the values for the monitoring times in the CPUs differ, the higher values always apply.
Calling OB 83
After transferring the parameter data records to the desired modules, OB 83 is called. The
sequence is as follows:
1. After you have made the parameter changes to an module in STEP 7 and loaded them in
RUN in the CPU, the OB 83 is started (trigger event W#16#3367). Relevant in the OB start
information are the logical base address (OB83_MDL_ADDR) and the module type
(OB83_MDL_TYPE). From now on, the input and/or initial data of the module might no longer
be correct, and no SFCs that send data records to this module may be active.
2. After termination of OB 83, the parameters of the module are reset.
3. After termination of the parameter reset operation, the OB 83 is started again (trigger
event W#16#3267 if the parameterization was successful, or W#16#3968 if it was
unsuccessful). The input and initial data of the module is the same as after an insertion
interrupt, meaning that under certain circumstances may not yet be correct. With immediate
effect, you can again call SFCs that send data records to the module.
246
One-sided I/O of previous
master CPU
are no longer addressed by the
CPU.
Output modules output the
configured substitute or holding
values.
One-sided I/O of new master
CPU
are given new parameter
settings and updated by the
1)
CPU.
Switched I/O
continue operation without
interruption.
System Manual, 09/2007, A5E00267695-03
S7-400H