Daisy chaining

A project log for Ø32 BLDC Controller

Miniature closed-loop controller for brushless DC motors

christopher-xuChristopher Xu 08/27/2023 at 17:300 Comments

One feature of this motor controller is that it has two power and two RS485 ports so it can be easily daisy chained with other. This week I spent a few days developing a simple 3-byte serial protocol that allows for bidirectional communication between multiple motor controllers and a master device (Teensy 4.0) for messages like set voltage, set current, get position, etc. It's like CAN, but I had to make do with a microcontroller without a CAN peripheral. 

The goal is reduce the number of wires running along a robot, especially for serial linkages. The limit is currently around 4 motors in series at 500Hz because only a certain number of bytes can fit within a certain time frame and all the current passes through one board, but I think it's worth the wiring convenience. 

Also, here's the robotics project I'm using these for: