Farnell TRC-8543, Руководство пользователя

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Connector Pin Signal Name
8 NC
9 V
SUP
CAN Bus Topology and Termination
A CAN bus consists of two or more CAN nodes cabled together. The CAN_H and
CAN_L pins of each node are connected to the main CAN bus cable through a short
connection known as a “stub.” The pair of signal wires, CAN_H and CAN_L,
constitutes a transmission line. If the transmission line is not terminated, each
signal change on the bus causes reflections that may cause communication errors.
High-Speed/Flexible Data-Rate CAN
Because the CAN bus is bidirectional, both ends of the cable must be terminated.
However, this requirement does not mean that every node on the bus should have a
termination resistor; only the two nodes at the far end of the cable should have
termination resistors.
The following figure shows a simplified diagram of a CAN bus with multiple CAN
nodes and proper termination resistor (R
t
) locations.
Figure 5.
CAN HS/FD Bus Topology and Termination Resistor Locations
Low-Speed/Fault-Tolerant CAN
Every device on a low-speed/fault-tolerant CAN network requires a termination
resistor for each CAN data line: R
RTH
for CAN_H and R
RTL
for CAN_L.
The following figure shows a simplified diagram of a low-speed/fault-tolerant CAN
bus with termination resistor placements.
© National Instruments
9
TRC-8543