Hi experts,

I'm starting a new project and it is the first time to use S7300plcand wincc scada.I have several questions about the communication.

There are two cranes working either individually or master/slave. Also, there is a wincc scada to log the alarms etc.

Each crane has it's own s7-300 (cpu315 2pn/dp)plc. These twoPLCshave tocommunicate with each other to make master/slave operation. Weprefer scalance wireless devices to establish this. Scalance device is using profinet.

Also, there are frequency inverters driven by plc over profibus.

There is no problem when the cranes are working individually.

But, howcan wecommunicatetwo plcin master/slave mode. Slave plc needs the digital and analog signals from master plc. How ever i have to collect some signals from both plc to record in scada pc.

The profibus port is busy by reason of VFDs.

In profinet network, scada has to be master too. So that, how can iset communicationbetween two PLCs?

Otherwise, i have to write some codes in scada to readsignals fromplc Aand write to theplcB, orvice versa.But, it's so difficult.

Thanks.