CANFDNET-400U
High-Performance Four-Channel CANFD Bus-to-Ethernet Converter User Manual
©2021 Guangzhou ZLG Electronics Technology Co.,Ltd.
8
User Manual
2.5 Terminal Resistance DIP Switch
To enhance the reliability of CAN communication, the two endpoints of the CAN bus
network usually need to be equipped with terminal matching resistors. The value of the
terminal resistor is determined by the characteristic impedance of the transmission cable.
For example, if the characteristic impedance of the twisted pair is 120 ohm, the two
endpoints on the bus should also integrate 120-ohm termination resistors. The
CANET-8E-U interface card adopts CTM8251KT transceiver. If other nodes on the
network use different transceivers, the terminal resistance must be calculated separately.
The function of the CAN bus terminal resistor:
Improve the anti-interference ability to ensure that the bus quickly enters the
recessive state;
Improve signal quality.
CANET-8E-U uses a mechanical switch to select a terminal resistor. The DIP switch
is at the bottom of the device, as shown in Table 2.2. The device's DIP switch is "ON" by
default; that is, the default access terminal resistance is 120 ohm.
Table 2.2 CANET-8E-U terminal resistance DIP switch
Description
DIP switch
The corresponding CAN channel connects
to 120 ohm
or
The corresponding CAN channel has no
access resistance
