How to mount AksIM encoder next to the electric motor? How to shield from external magnetic field?

AksIM is a magnetic encoder and relies on detecting the magnetic field of the actuator (magnetized ring).

If there is unwanted stray external magnetic field present, it may disrupt the operation.
There is no rule of thumb that would estimate the effect and required distance between the motor and encoder readhead as there are too many different variables, such as motor size and shape, used materials and magnetic saturation, shaft material and design, etc. Any software for simulation can be used such as Femm, Comsol, Vizimag or similar to estimate the magnetic field strength at the readhead.

If encoder experiences issues during operation, it is suggested adding some kind of shielding between the source of stray magnetic field and encoder readhead. Any ferromagnetic plate is recommended (ordinary Fe), 0.5 to 1 mm thick, to cover coils and magnets on the place of sensor and at least 10 mm around it. Assembly should be mounted in this order: Motor – shield – air gap – encoder ring – readhead.

For more information refer to the datasheet , chapter “External magnetic field“.