We have been using a configuration with two VESCs 75/300 connected to a Teensy 3.2 which shares the same battery ground with the VESCs. The Master VESC is connected with TX, RX, GND and 5V to the Teensy and the second is connected through CAN to the master VESC. (The 5V is just to check if the VESC is powered not really powering anything and has a resistor in series to limit the current)
This setup have been working for quite some time now but the other day we were testing our motor dyno with one of the VESCs connected to the battery and to the VESC tool through USB and the other one connected to the Teensy like before (TX, RX, GND and 5V). The VESC connect to the PC was working as a Generator while the one connected to the Teensy was driving the motor.
Everything was working well or the first few runs but suddenly the we saw smoke coming from the cables that were connecting the VESC to the Teensy and we immediately stopped testing. Upon further debug we came to the conclusion that the GND cable melted and the some was from there. The cable was really hot. We think that somehow, at least some of, the current that the VESC was pulling came from that 0,5 mm^2 cable instead the really thick 70 mm^2 power cable.
After that we check with the multimeter that the GND on the VESC's Serial connector is connected to the Supply GND of the VESC.
Our question is, in a setup like ours where the microcontroller shares the GND with the VESC is there the need to connect the GND from the VESC's Serial connector to the Teensy? Or should we just connect TX and RX? We don't really know how we didn't had problems with this before given the setup has been like these for more than 2 years now.
Thanks in advance!
gnd return, complete cabling schematic should be taken into account, all devices, instruments, mains etc..
Could you please elaborate what did you meant with your answer?
show how your system had been connected,
Here you have it, Generator VESC is applying break current to the motor. Connection names on the cables from the Teensy to the VESC are the label on the VESC connector. As I said on the first post the 5V are used to sense that the VESC is on and not to power anything.
For some reason the picture disappeared...
I don't think the 5V from the Teensy to the Motor VESC is a good idea, be better to use an opto-isolator.
You've also got a ground loop from the 12s battery to the DC/DC to the teensy to the motor VESC to the 12s battery. If you bin the DC/DC you'll be fine. If you think the DC/DC is necessary then cut either the Teensy ↔ DC/DC gnd or the Teensy ↔ Motor VESC gnd.