Devicenet Communications Connection Example - Omron OMNUC W Series Manual

4 Connectors

4.5.2 DeviceNet Communications Connection Example

4.5.2 DeviceNet Communications Connection Example
Connect terminating resistors
to both ends of the trunk line.
T
T-branch
Tap
Use special
DeviceNet cables.
Drop line
Node
4
A DeviceNet network configuration is shown below.
24 VDC
Trunk line Trunk line
T T
T-branch
Tap
M
Drop line Drop line
Node M
Node
Fig. 4.2 Network Connections
Configuration Elements
The network is configured from the following elements.
Nodes
A node is either a slave that connects to an external I/O, or the master that manages the
external I/O of the slaves. There are no restrictions on the location of the master or slaves.
Any node in Fig 4.2 can be the master or a slave.
Trunk Line and Drop Lines
A cable with a terminator on each end is a trunk line. Any cable branching from the trunk
line is a drop line. The length of the trunk line and the maximum network length are not
necessarily the same. Use special DeviceNet cables for the trunk line and all drop lines.
Either thick cables or thin cables may be used.
Connection Methods
There are two methods that can be used to connect DeviceNet nodes: T-branch connections
and multi-drop connections.
• T-branch connections: Used to branch a drop line using a T-branch Tap.
• Multi-drop connections: Used to connect a node directly to the trunk line or directly to a
drop line.
As shown in Fig 4.2, both T-branch connections and multi-drop connections can be used
together in the same network.
Communications
Use special
power supply
DeviceNet cables.
Power Supply Tap
or T-branch Tap
Trunk line
T
T-branch
T-branch
Tap
Tap
Drop line
Drop line
T-branch Tap
Node
T
Drop line
Node
Drop line
M Node
Node
4-16
Connect terminating resistors
to both ends of the trunk line.
Trunk
Trunk
Trunk
M
M
line
line
line
T
Node Node
Node
T: T-branch connection
M: Multi-drop connection
Trunk and drop lines: Use special
DeviceNet cables (5-wire cable).
T-branch
Tap