roaming | Adrian - 3/21/2017 18:27
I know that a CANBus network needs a terminator, and I think that the terminator is just a resistor. What exactly is it for? Why is it needed? A CANBus cable has 4 wires, +, -, CAN high, and CAN low. Which of these is the terminator between? I assume the CAN high and low? Why?
Just one of those things I've wondered for a long time.
Adrian
Think about a rock thrown into a pond. It creates ripples, and when the ripples hit the shore, they bounce back or reflect in the direction from which they came. So you have the main ripples headed toward shore, and the reflected ripples headed back to the middle of the pond. A similar thing happens with electrical signals on a CAN bus. When the "ripples" hit the end of the line (unterminated), they reflect back, causing the reflected ripples to interfere with the "main" ripples. A terminator essentially absorbs the ripples when they reach the end of the line, so that they can't reflect.
A couple of articles that might help:
https://en.wikipedia.org/wiki/Electrical_termination
http://electronics.stackexchange.com/questions/55389/why-does-the-c... |
CANBus terminators... what are they anyway?
