The key role of terminal resistance in CAN bus communication and its practical application

In CAN bus communication, terminal resistors are a crucial component. According to ISO11898-2, a 120Ω terminal resistor must be installed at both ends of the bus, while the intermediate nodes do not need to be equipped with terminal resistors. If we communicate without adding terminal resistors, we will find that the message cannot be sent normally and the associated waveform will also have problems. This is because the terminal resistor affects the speed of the falling edge, making it unable to reach the recessive state quickly. At the same time, the absence of terminal resistors will also cause error frames. Therefore, we need to add terminal resistors correctly to ensure the normal communication of the CAN bus.