CAN / DeviceNet topology
CAN/DeviceNet is a 2-wire bus system, to which all participating devices are connected in parallel (i.e. using short drop lines) (Fig. DeviceNet Topology). The bus must be terminated at each end with a 120 (or 121) Ohm terminating resistor to prevent reflections. This is also necessary even if the cable lengths are very short!
![CAN / DeviceNet topology 1:](Images/gif/2578514571__Web.gif)
Since the CAN signals are represented on the bus as the difference between the two levels, the CAN leads are not very sensitive to incoming interference (EMI): Both leads are affected, so the interference has very little effect on the difference.
![CAN / DeviceNet topology 2:](Images/gif/2578517003__Web.gif)