fault in s7400 cards

Then system polls S7-400 modules in seconds intervals to detect insertion
or removal. To enable the CPU to detect the removal and insertion of an
S7-400 module, a minimum time interval of two seconds must expire
between removal and insertion. This minimum time is slightly higher for
other modules.If you remove a configured module in the RUN mode,
OB83 is started. Since the existence of modules is only monitored at
intervals of one second, an access error may be detected first if the
module is accessed directly or when the process image is updated.
If you insert a module in a configured slot in the RUN mode, the
operating system checks whether the type of the module inserted
corresponds to the recorded configuration. OB83 is then started and
parameters are assigned if the module types match.