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hall sensor data

Posted: Mon Mar 27, 2023 7:58 am
by anaveed
In our application, we need to fetch encoder data for odometry. In API of DCC1100, I didnt find anywhere about getting encoder data. Could you please tell me if I am missing something or is there a way to get the encoder data?

Re: hall sensor data

Posted: Mon Mar 27, 2023 9:43 am
by mparadis
The controller keeps track of hall effect sensor data in the form of the "Position" property.

Re: hall sensor data

Posted: Tue Mar 28, 2023 2:31 am
by anaveed
Thanks for your prompt feedback. Let me extend my question further,

if I am using DCM4105_1 BLDC motor that has 8 poles and 3 phases that means it has 24 commutations per rotation or 24 pulses from encoder on one complete revolution. Since the motor has 106:1 gear ratio, does that mean it will take 24 *106 commutation per rotation of output shaft? what actually getPosition() API of motor driver DCC1100 offers? Does it tell the position of output shaft?

Re: hall sensor data

Posted: Tue Mar 28, 2023 7:58 am
by mparadis
Yes, your math is correct, it will take roughly 24*106 hall effect "position" units for one rotation with this motor. Keep in mind that the gear ratio is actually 105⅝ : 1, so if you use 106 as your gear ratio, the position will be inaccurate when calculating many rotations.

The "Position" from the API resets every time the BLDC channel is opened or closed, so it cannot tell you the absolute position of the motor unless you start at a known position every time. If absolute positioning is important, you may need to add an encoder with an index channel, or some kind of limit switch into your system. We plan on selling encoders that will fit on the rear shaft of these motors soon, since the hall effect sensors don't have an index and aren't precise enough for some positioning applications.