Q: What is the role of the red switch on the P004?
A: The red switch on P004 is used to control the CAN communication termination resistor. Switch #1 corresponds to high speed CAN communication and switch #2 corresponds to vulgar CAN communication. The switch should remain in the ON position when the CAN line termination resistor is required.
Q: There are two groups of CAN H and CAN L on the P004, can I access one of them at will?
A: No. The two groups of pins correspond to high speed CAN type and low speed CAN type. According to the wiring definition of the device, use the CAN communication pins with corresponding numbers.