98 • Fieldbus CommunicationETHERNETWAGO-I/O-SYSTEM 750ETHERNET TCP/IP4.1.2.4.1 Static Configuration of the Transmission ModeUsing static configuration, both link partners are set to static transmission rateand duplex mode. The following configurations are possible:- 10 Mbit/s, half duplex- 10 Mbit/s, full duplex- 100 Mbit/s, half duplex- 100 Mbit/s, full duplex4.1.2.4.2 Dynamic Configuration of the Transmission ModeThe second configuration option is the autonegotiation mode which is definedin the IEEE 802.3u standard. Using this mode, the transmission rate and theduplex mode are negotiated dynamically between both communicationpartners. Autonegotiation allows the device to automatically select theoptimum transmission mode.NoteTo ensure a correct dynamic configuration process, the operation mode for theautonegotiation of both communication partners must be supported andactivated.4.1.2.4.3 Errors Occurring when Configuring the Transmission ModeInvalid configurations are listed below:Problem Cause SymptomsMismatch of thetransmission rateOccurs when configuring onelink partner with 10 Mbit/sand the other one with 100Mbit/s.Link failureDuplex modemismatchOccurs when one link partneris running in full-duplex andthe other in half-duplex mode.Faulty or discarded data packets aswell as collisions on the medium.Mismatch usingautonegotiationOccurs when one link partneris running in auto-negotiationmode and the other one isusing a static configuration ofthe transmission mode in full-duplex operation.The link partner, which is inautonegotiation mode, determines thenetwork speed via the paralleldetection procedure and sets the duplexmode to half-duplex. If the device isoperating in full-duplex mode withstatic configuration, a duplex modemismatch will occur (see above).
