Technical data

11.3 Communication Between the DP Master and the DP
Slave Station
During the start-up phase, the CP checks whether the DP slave station is
operational by fetching diagnostic data.
This job is repeated (controlled cyclically using the DP polling list ) until the
slave responds with the requested diagnostic data. If the received
diagnostic data do not indicate any further errors, the DP slave is then
assigned parameters and configured.
If no error is signaled after the second request for diagnostic data, the CP
changes to the mode "cyclic data exchange" with the DP slave.
DP master
DP slave
Request slave diagnostic data 1st time
Send parameter assignment data
Fetch configuration data
Send configuration data
Request slave diagnostic data 2nd time
If no error was signalled
continue with cyclic
data exchange
Send output data to DP slave
Receive input data from DP slave
Cyclic data
exchange
phase
Start-up
phase
Repeat job until
the slave replies
Request
Response
Fig. 11.4 Communication between DP Master CP 5430 TF/CP 5431 FMS and DP Slave
B8976060/02 Distributed I/Os (DP)
11 - 9 Volume 1