Motors not working

Technical Motors
1

We have two problems on our robot:

A Falcon motor with MaxPlanetary gearbox is attached to a winch. When energized the motor rotates the winch spool a half revolution or so then stops - regardless of direction. Should run until controller is released or a hard or soft limit is hit.

Another Falcon does not appear on the CAN bus. The can bus is wired with a bus wire from power distribution hub to the roborio and the drive train motors are tapped into the bus. Another (the one described above) is attached to a spur line from the CAN bus and is recognized by the RoboRIO. The other Falcon is connected further downstream on the spur CAN line and is not showing on the bus. I suspect that the SparkMAX further downstream on the same CAN spur line (connecting a NEO550 with an Ultraplanetary gearbox) are not on the CAN bus either. I heard that terminating the CAN bus spur with a 120 ohm resistor might solve this. What else should we look for in our troubleshooting?

Thanks for any advice you or your electronics expert(s) might offer is very welcome.

Our competition starts Friday and we are a rookie +1 team (with mostly rookie team members after sitting out during Covid…)

2

The standard recommendation is that your CAN bus be a single line topology running from the roboRIO at one end, all other devices in the middle, to the PDP/PDH at the other. Both the roboRIO and the PDP/PDH have terminating resisters, but the latter requires jumper/switch configuration to enable it,

I’m aware that many teams do use spurs or star topologies, but you may want to stick to the simple approach unless you’re confident you know what you’re doing.

Regarding your winch problem, this may be a software issue and we’d need to see your code to help further. Can you share a link, say to Github?