Correct Network Topology for CAN Bus Hardware Systems

As robotics platforms scale in complexity, running individual signal wires from a central computer to every single actuator and sensor creates a massive, failure-prone wiring harness. Transitioning your design to a CAN Bus network resolves this layout crisis, but only if your team implements correct network topology and termination.

### 1. Strict Linear Bus vs. Star Topology

A common error made by hardware teams is layout out their CAN network like a "star," where every individual device runs back to a central node. This layout introduces complex signal reflections that corrupt data packets. A robust CAN network must be laid out as a strict **Linear Bus**, where a single main trunk wire runs through the vehicle, and individual devices tap into it via ultra-short "stub" lines.

### 2. The Necessity of 120-Ohm Termination Resistors

An un-terminated CAN network will suffer from massive signal echoes that completely paralyze communication loops. To absorb these electrical reflections, you must place a single **120-Ohm termination resistor** at the absolute physical beginning and physical end of your primary bus line. 

### 3. Differential Noise Immunity

The reason premium aerospace and robotic components rely on CAN Bus is its use of a **differential signal** across two paired wires: CAN High and CAN Low. By measuring the voltage *difference* between the two lines rather than a raw voltage relative to ground, the signal remains completely immune to massive electromagnetic interference (EMI) thrown off by high-power brushless motor phases nearby.