We’re having issues with several of our Neo motors on our robot not running every few seconds in an inconsistent pattern. Every once in a while there will be a buzzing noise coming out of the motor.
Here’s the behavior when I’m simply running pwm back and forth. You can hear the buzzing and see by the spark max light that sometimes the motor simply doesn’t run when I send it pwm.
All sparks are at firmware 1.5.2.
Our mentor said that he recognized the sound as a peak current limit getting tripped; I don’t remember the exact wording but we tried upping our current lims to the default of 80 but that made no effect either.
We’ve also tested all our anderson connectors and they are secure.
I’m not sure if it’s a torque thing either; we had a 7:1 775 their before (we switched it out with a neo to increase power there) and it worked fine albeit hot.
I can’t consistently make out the MAX light, so I’m not sure if this is only happening as you go from zero to nonzero throttle, or while holding throttle steady.
In any case, check your electrical connections, especially the encoder wires from NEO to MAX. If you have an oscilloscope, you may want to check the encoder signals from the MAX’s data port.
I can’t quite make out the colors on the Spark Max but it looks like it’s going yellow when the motor stops running, is that correct? If that’s the case, the yellow LED blink code is for brushed motors, not brushless. This could happen if there’s inconsistencies in your CAN bus and the Spark Max isn’t talking consistently with the roboRIO. Check your CAN connections throughout the bus, especially the CAN connector going into the Spark Max.
The issue occurs only when starting from a full stop. When it gets “stuck”, it doesn’t matter if we go from zero to full throttle or gradually increase throttle (all done in PWM mode). The LED on the Spark Max is a solid green or red color (or flashing green/red when not at full throttle) but is never yellow. The current theory that we are working on is that the motor simply needs to provide more power but the Spark Max is preventing it from drawing too much current; the 775 that we had on there before never did this but did overheat (thus leading us to think that it might be a current draw issue). We will definitely check and re-check the CAN connections and the encoder wires, though.
I wired a brand new Spark Max and this seemed to solve the issue. It’s strange though; I looked closely at the crimps on the original controller and they seemed to be seated completely correctly – hooked over the flap, not partially in, correct amount of wire in the contact. I’m rather confuzzled, maybe we got a bad controller?
Are the contacts at an angle in the connector shell? I have seen deformed crimps cause the contact to be rotated along the axis of the wire so that only one side makes contact with the contact in the mating connector.
