Rotor Position Encoder
dev_motor_controller_4808 incorporates an integrated rotor position encoder based on the Austria Micro AS5047p magnetic encoder. The AS5047p device returns 14 bits of rotational position at a maximum rate of 28k RPM.
Encoder Target
AS5047p magnetic target
The AS5047p returns the position of a diametrically magnetised cylindrical magnet mounted to a rotating structure at a fixed distance from the surface of the sensor.
| Magnet type | Cylindrical diametrically magnetised Neodymium Iron Boron (NdFeB) N35 |
| Potential part number | Radial Magnets Inc 9042, Digikey 469-1070-ND |
Magnet mounting requirements
In practice the AS5047p is quiet tolerant to magnet misalignment and in most cases will produce a reasonable output. Mounting guidelines are presented below.
| Vertical mounting distance | Between 0.5mm and 1.8mm from the surface of the sensor |
| Suggested magnet size | 6mm diameter, >= 2.5mm height |
| Bz (Orthogonal magnetic field strength) | 35mT - 70mT peak field strength at a radius of 1.1mm |
For further detailed information consult the AustriaMicroSystems AS5047p datasheet. Although it is a different sensor the AS5040 datasheet also offers useful mounting guidelines.
Magnet mounting example
