NI NI-9853, Руководство пользователя

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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.
Figure 1 shows a simplified diagram of a CAN bus with multiple CAN nodes and
proper termination resistor (R
t
) locations.
Figure 2. CAN Bus Topology and Termination Resistor Locations
CAN
Node
CAN
Node
CAN
Node
Rt Rt
CAN
Node
CAN_H
CAN_L
CAN_H
CAN_L
CAN_H CAN_L CAN_H CAN_L
Bus Cable Length
Stub
Length
Connecting a CAN Bus to the NI-9853
You can connect each port of the NI-9853 to any location on a CAN bus. Figure 2
shows one example of connecting CAN0 of the NI-9853 directly to one CAN node,
and CAN1 directly to another CAN node. CAN1 requires an external power supply on
the CAN bus.
Figure 3. Connecting Both Ports of the NI-9853 to CAN Buses
Cable Specifications
Cables should meet the physical medium requirements specified in ISO 11898,
shown in the following table. Belden cable (3084A) meets all these requirements
and should be suitable for most applications.
Characteristic Value
Impedance 95 Ω min,
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NI-9853