DESIGNER’S HANDBOOK 4189350049C EN
Page 33 of 206
Fig. 6. Mounting screws and smart-grip clamps are pre-mounted on the XDi unit
4.4
Installing a CAN bus system
4.4.1
XDi CAN bus ports
The XDi base unit is equipped with two CAN bus ports, and CANopen is the standard interface protocol. The
unique DEIF XDi-net Plug & Play extension to the CANopen protocol is used in all DEIF standard libraries for easy
data sharing and is also used in many custom specific libraries, to make system setup and integration easy.
The following sections describe the basic CAN installation information. For more detailed information, please
consult the “XDi-net/CANopen reference manual.
4.4.2
CAN bus system wiring
The XDi unit can be connected to the CAN bus either by a short drop cable to the backbone or by daisy-chaining
the backbone from unit to unit (see following drawing).
The standard terminal block, with a single row of 5 screw terminals, supplied as standard for the XDi, is most
appropriate for drop cable connection. Daisy chaining will require two wires to be mounted in each terminal
location.
Recommendation: if daisy chain is the preferred installation form, we recommend that you order the XDi unit with
either the double screw terminal option or the double spring terminal option. (See the XDi data sheet for ordering
information)
4.4.3
CAN backbone and Termination
4.4.3.1 Termination
The CAN bus must be terminated in each end of the CAN bus cable line by a 120
Ω resistor
. To make termination
easy, the XDi has a built-in 120
Ω termination resistor. Set the switch to ON (see drawing) to activate the
termination. Each of the two CAN ports has a separate built-in termination resistor and ON/OFF switch.
