Setting Electrical Angle Zero by Zeroing Encoders

hardware support
1

Hi All,

I’m working with a project that uses AMT212B encoders to commutate some BLDC motors. These are absolute encoders, with a non-volatile, user-settable zero.

I’m “sprucing up” everything in preparation for a public demo, and to streamline the startup sequence I’m trying to eliminate the need for each motor to run sensorAlign() on startup. For the purposes of the project, I have several identical systems (MCU + multiple BLDC motors) that I need to have running the same code, so simply hardcoding the correct zero angle offset isn’t a viable option. Instead, I would like to write a “calibration script” that zeros the encoders at the correct angle, so I can set all motors’ zero_angle_offset to zero in code, and skip the sensorAlign() step at startup.

I had been planning to simply replicate the steps of sensorAlign() in my own code but replace the line zero_electric_angle = electricalAngle() with ZeroEncoder(), but I’m finding I can’t do that since setPhaseVoltages() is a private function. Does anyone have any advice for how to replicate the functionality of sensorAlign() in my own code?

Thanks.

squirellydan

2

Hi,

setPhaseVoltage will be public in the next release… I just merged this to the dev branch, so you can check out the dev branch if you’d like.

But may I ask why not use the function initFOC() which takes the electrical angle as input parameter? If you provide the electrical angle and direction to initFOC(), the alignment will be skipped…

3

Thanks! That’s perfect.

And in my case I have two systems (2 distinct MCUs) that each have multiple motors, and need to be running the same code. So if I just pass the electrical angle to initFOC, each time I want to deploy the code to an MCU, I would need to manually change the electrical angles to be correct for that individual system.