High-Speed/Flexible Data-Rate CAN
Table 5.
ISO 11898 Specifications for Characteristics of a CAN_H and CAN_L Pair of
Wires
Characteristic
Value
Impedance
95 Ω min, 120 Ω nominal, 140 Ω max
Length-related resistance
70 mΩ/m nominal
Specific line delay
5 ns/m nominal
Low-Speed/Fault-Tolerant CAN
Table 3.
ISO 11898 Specifications for Characteristics of a CAN_H and CAN_L Pair of
Wires
Characteristic
Value
Length-related resistance
90 mΩ/m nominal
Length-related capacitance: CAN_L and ground, CAN_H and ground, CAN_L
and CAN_H
30 pF/m nominal
High-Speed/Flexible Data-Rate CAN
The termination resistors (R
t
) should match the nominal impedance of the CAN
cable and therefore comply with the values in the following table. The onboard,
software-selectable termination has a nominal value of 115 Ω. If you are not using
the onboard termination, use the values listed in the following table.
Table 5.
Termination Resistor Specification
Characteristic
Value
Condition
Termination resistor, R
t
100 Ω min, 120 Ω nominal,
130 Ω max
Minimum power dissipation: 220 mW
Low-Speed/Fault-Tolerant CAN
Unlike High-Speed/Flexible Data-Rate CAN, Low-Speed/Fault-Tolerant CAN requires
termination at the Low-Speed/Fault-Tolerant CAN transceiver instead of on the
cable itself. Termination requires two resistors, RTH for CAN_H and RTL for CAN_L.
© National Instruments
11
TRC-8543
Содержание TRC-8543
Страница 1: ...TRC 8543 2022 06 30 ...