Termination Of The Devicenet Network - Omron SmartController EX User Manual

6.4 DeviceNet Physical Layer and Media
Item Connector Style
1 Unsealed screw con-
nector
2 Unsealed hard-wired
3 Sealed mini-style
4 Sealed micro-style

Termination of the DeviceNet Network

The DeviceNet network uses the Controller Area Network (CAN) bus as the physical layer.
This requires that the trunk line of your DeviceNet network be terminated with a resistor at
each end. This terminates the signal lines.
The terminating resistor:
Prevents reflection of communication signals on the network.
l
Connects the two signal conductors.
l
Must be sealed if the end node uses a sealed tee.
l
Must be open if the end node uses an open-style tap.
l
The SmartController EX has a terminating resistor built-in, which can be used for one end of
the DeviceNet network.
It is possible to disable this resistor by moving the JP2 jumper, which is internal to the
SmartController EX. If you disable this resistor, a terminating resistor must then be used
whenever a short drop line exceeds 6 m (20 ft). See the following figure.
66
1 2
Figure 6-4. DeviceNet Connector Styles
Table 6-7. DeviceNet Connector Style Descriptions
SmartController EX User's Guide
3
Description
Uses screws to attach wires to a removable con-
nector
Uses wires attached directly to screw terminals
Attaches to taps and thick or thin cable
Attaches to thin cable only – has a reduced current
rating
4
11069-000 Rev. H