Situation:
I’m building an e-scooter that uses 2x Little FOCer 3.1 VESC’s driving 2x Lonnyo 11 inch motors. The controllers are 2 physically seperate controller units, not a dual motor controller packaged into one unit. The two VESC’s are setup to talk to eachother over CANBUS. Additionally, I’ve got a Trampa VESC Display unit that will serve as the on-board spedometer, will allow me to switch between 3 seperate driving modes (Hi, Mid, Lo), and let me monitor metrics. All up and in-short, this is a pretty basic VESC display use-case, being used in a fairly simple and straightforward application scenario.
My problem:
So, in order to operate, the VESC display requires the following connections: +12v, Ground, CAN Hi, CAN Lo. I’m getting my 12v rail from a potted step down converter that’s being fed by my battery via a simple tap, so the +12v and G wires are connecting directly to a busbar that is hooked to the step-down converter. My controllers are talking to eachother via the CANBUS, so I made a 2pin JST splitter that simply duplicates CAN Lo and CAN Hi into two seperate, identical connectors. One of those 2 connectors is linked to the CANBUS Lo and Hi on the 2nd VESC, and the other is linked to the 2 CANbus wires from the VESC Display. This pretty much works. I see values from the scooter being displayed…except the values being displayed by the display unit keep bouncing back and forth (pretty fast, like several times per second) between what looks like the 2 seperate values being read from EACH controller. I.e. if the speed is calculated as 15mph on one motor and the other motor is calculating as 17mph, then it will show both ‘actual speed’ values, but it just skips back and forth between the two different numbers.
My suspicions:
This is probably being caused by the fact that the CANBUS is terminated automatically at each VESC and my wiring sticks the Display between both units and not connected directly to the PRIMARY (throttle connected) controller and that the splitter I’m using is allowing the display to hear CAN messages coming from both controllers and not just one.
My question, basically:
Since I can’t really daisy chain these three devices together (there aren’t IN and OUT connectors, like you’d usually see in a BUS network, what is the right way to wire everything to allow the display to hear/show telemetry data smoothly without rapidly bouncing back and forth between competing values, presumably being fed to the display from 2 seperate data sources (VESC’s).
Pls help. let me know if you need more specifics or any other info to better understand the matter at hand. This monster is soooo close to being R2R, and I’ve got a burning [f-ing] desire to ride it. Any assistance would be greatly appreciated.
Tks
Nick