Communication47CommunicationWhat this chapter containsThis chapter describes the communication on an EtherCAT®network.EtherCAT® frame structureIn EtherCAT, the data between the master and the slaves istransmitted in Ethernet frames. An EtherCAT® Ethernet frameconsists of one or several EtherCAT® telegrams, each addressingindividual devices and/or memory areas. The telegrams can betransported either directly in the data area of the Ethernet frame orwithin the data section of an UDP datagram transported via IP.The EtherCAT® frame structure is pictured in following figureEtherCAT® frame structure. Each EtherCAT® telegram consistsof an EtherCAT® header, the data area and a working counter,which is incremented by all EtherCAT® nodes that are addressedby the telegram and have exchanged associated data.Figure 6. EtherCAT® frame structure.
