Other Parts Discussed in Thread: TIDA-010026
The shield wire of RS485 communication line connects the metal of D-sub.We find that if we want to pass the EFT test, Y capacitance(1nF/2KV) is very important.During the EFT test, the noise signal is coupled to the shield.Why does this capacitor make communication better? Why don't you worry about the noise from the shield wire going to the inside of the circuit board?
We can prove that this capacitor is the key to communication stability through a lot of experiments on different circuit boards, but we don't know the principle. I hope you can tell us why it is really reusable.