Fig. 8 devicenet topology, Maximum cable distance, Devicenet network topology – Yaskawa DeviceNet Option Card CM059 User Manual

Page 67

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

Tap

Multi-Port

Tap

Node

Multi-Port

Tap

Node

Terminating
Resistor

Multiple Node

Daisy Chain

Drop Line

Multiple Node

Branching
Drop Line

Fig. 8 DeviceNet Topology

Dropline