3-1
Section
Network Configuration
23
3-1-2 Connections
The trunk line is a cable to which Terminating Resistors are connected at the
ends. Drop lines are cables that branch from the trunk lines. A special 5-wire
cable is used for both the trunk lines and the drop lines.
Branching Patterns
Branching Patterns from Trunk Line
Drop line
T-branch Tap
Trunk line
Node
Trunk line
T-branch Tap
Trunk line
Node
T-branch Tap
Node
Node
Trunk line
Multi-drop
Trunk line
Node
Trunk line
1.One drop line from
trunk line
2.Three drop lines (maximum)
from trunk line
3.Node connected directly to
trunk line
Branching Patterns from Drop Line
Drop line
T-branch Tap
Trunk line
Node
Trunk line
T-branch Tap
Trunk line
Node
T-branch Tap
Node
Node
Trunk line
Multi-drop
Trunk line
Node
Trunk line
4 One drop line from
drop line
5.Three drop lines (maximum)
from drop line
6.Node connected directly to
drop line
Various combinations of branching patterns can be used on the same network,
as shown in the following diagram. Any number of nodes up to 63 can be con-
nected onto a single drop line.
Communications
power supply
Terminating
Resistor
Node
Node
Drop line
Node
Node
Drop
line
Trunk line
24 VDC
Node
Node
Node
Node
Node
Node
Power Supply Tap
or T-branch Tap
Trunk line
Drop
line
Terminating
Resistor
Reference 1. A node can be connected directly to the trunk line with the multi-drop meth-
od, but it is easier to connect a node to a drop line.
2. Multi-drop connections with thick cables cannot be used with the connectors
supplied with the Unit because the cables are too thick. Use the following
connectors for multi-drop connections with thick cables. (For further details,
refer to Appendix C Standard Models.)
XW4B 05C4-T-D (w/o set screw) (made by OMRON)
Use a T-branch Tap instead if the connector extends too far from the side of
the Master Unit or DeviceNet Interface Unit and interferes with the Unit in the
adjacent slot.
3. When using thick cable, wire the cable with enough extra cable so that the
connector won’t become disconnected accidentally when pulled.
Trunk and Drop Lines