What is the monitoring time for a S7-300 CPU on the PROFIBUS when
a DP slave is not available?
You are operating a PROFIBUS network with DP slaves on the
PROFIBUS interface of your CPU and during Startup you wish to check
whether the expected configuration matches the actual
configuration. There are two different times given in the
Properties dialog of the CPU, in the Startup tab.
Fig. 1: Startup properties of the CPU
An S7-300 CPU waits the time for transfer of the parameters to
the modules until it checks whether there is a difference between
the expected configuration and the actual configuration. If at this
point in time one of the DP slaves is not available and there
should not be startup if there is a difference between the expected
configuration and the actual configuration, then the CPU goes into
STOP mode. In this case the CPU has to be set back into the RUN
mode when all the DP slaves are available.