264 • ETHERNET
Network architecture
Modular I/O System
ETHERNET TCP/IP
Wiring of the fieldbus nodes with 10Base-T technology
A crossover cable is required for direct connection of a fieldbus node to the
network card of the PC.
Fig. 5-2: Direct connection of a node with crossover cable
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If several fieldbus nodes are to be connected to a network card, the fieldbus
nodes can be connected via an ETHERNET switch or hub with straight
through/parallel cables.
TD+
TD-
RD+
RD-
TD+
TD-
RD+
RD-
TD+
TD-
RD+
RD-
TD+
TD-
RD+
RD-
hub
Fig. 5-3: Connection of a node by means of a hub with parallel cables
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A switch/hub is a device that allows all connected devices to transmit and
receive data with each other. This can also be viewed as a “data traffic cop”
where the hub “polices” the data coming in and going out so that it will be
transmitted to the correct node. WAGO recommends using a switch rather
then a hub, this will allow for a more deterministic architecture.
Attention
The cable length between the node and the hub can not be longer than 100 m
(328 ft.) without adding signal conditioning systems (i.e. repeaters). Various
possibilities are described in the ETHERNET standard for networks covering
larger distances.