Yaskawa DeviceNet Option Card CM059 - Manual (Page 67)

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DeviceNet Network Topology
The DeviceNet media has a linear bus topology. Terminating resistors are required on each end of the trunkline. Droplines as
long as 6 meters (20 feet) each are permitted, allowing one or more nodes to be attached. DeviceNet allows branching structures
only on the dropline. The figure below shows an example of a DeviceNet network. The thick lines indicate a trunkline, whereas
the thin lines indicate a dropline.
Maximum Cable Distance
The total amount of trunkline allowable on the network depends upon the data rate and the type of cable (thick or thin) used.
The cable distance between any two points in the cable system must not exceed the Maximum Cable Distance allowed for the
baud rate. For trunklines constructed of only one type of cable, refer to the following table to determine the Maximum Cable
Distance based on the data rate and the type of cable used. Cable distance between two points includes both trunkline cable and
dropline cable length that exists between the two points.
DeviceNet allows the use of either thick or thin cable to be used to construct trunklines. DeviceNet also allows a combination
of both types of cable to be used on the same network. To determine the maximum cable distance with a mix of both thick and
thin cable, use the following figure.
Table 50: Maximum Cable Distance Allowed per Baud Rate
Baud Rate
Maximum Cable Distance
for 100% Thick Cable
Maximum Cable Distance
for 100% Thin Cable
125 kbaud 500 meters (1640 feet)
100 meters (328 feet) 250 kbaud 250 meters (820 feet)
500 kbaud 100 meters (328 feet)
Zero Length
Drop Line
Node
Node
Node
Node
Node
Tap
Tap
Tap
Multi-Port
Tap
Node
Node
Node
Node
Node
Multi-Port
Tap
Node
Terminating
Resistor
Terminating
Resistor
Multiple Node
Daisy Chain
Drop Line
Multiple Node
Branching
Drop Line
Fig. 8 DeviceNet Topology
Dropline
Dropline
Dropline