User`s guide

Chapter 7: Adept DeviceNet
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:
l
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.
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.
Figure 7-5. DeviceNet: Connector, Internal CANPower OFF, Terminating Resistor ON
Adept SmartController EX User’s Guide, Rev. D
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