CAN-8124/CAN-8224/CAN-8424 User Manual
CAN-8124/ CAN-8224/ CAN-8424 User Manual (Version 2.0, Aug/2007)
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2.3 Wire connection
In order to minimize the reflection effects on the CAN bus line, the CAN
bus line has to be terminated at both ends by two terminal resistances as in the
following figure. According to the ISO 11898-2 spec, each terminal resistance
is set to 120
Ω
(or between 108
Ω
~132
Ω
). The length related resistance should
have 70 m
Ω
/m. The user should check the resistances of their CAN bus,
before they install a new CAN network as in figure 2-1.
Figure 2-1 wire connections
Moreover, to minimize the voltage drop over long distances, the terminal
resistance should be higher than the value defined by ISO 11898-2. Table 2-1
may be used as a reference.
Table 2-1 The relation between bus cable and length
Bus Cable Parameters
Bus Length
(meter)
Length Related
Resistance
(m
Ω
/m)
Cross Section
(Type)
Terminal
Resistance
(
Ω
)
0~40 70
0.25(23AWG)~
0.34mm
2
(22AWG)
124 (0.1%)
40~300 <
60
0.34(22AWG)~
0.6mm
2
(20AWG)
127 (0.1%)
300~600 <
40
0.5~0.6mm
2
(20AWG)
150~300
600~1K <
20
0.75~0.8.mm
2
(18AWG)
150~300
