China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Encoder magnetic rings are commonly used to measure and detect position and motion in mechanical systems. The number of poles is an important parameter that refers to the number of magnetic poles on the encoder ring or the number of poles in the inductor. The number of poles determines the resolution of the encoder, i.e. how many small changes in position or motion it can detect. To determine the number of poles of an encoder magnetic ring, the following steps can be taken:
1. Review the encoder specifications: First, you should review the encoder's specification or documentation provided by the manufacturer. These documents usually contain detailed information about the encoder, including the number of poles.
2. Observe the encoder's magnetic ring: If you have physical access to the encoder, you can directly observe the magnetic poles on the encoder's magnetic ring. Magnetic poles usually appear as small pieces of magnet or magnetic material distributed around the ring. You can count the number of magnetic poles and this will be the number of poles of the encoder.
Magnetic pole observation film/magnetic pole display card
3. Using the inductor output: Some encoders may contain information about the number of poles in their output signal. Check the specification sheet or data sheet of the encoder's output signal to see if there is information about the number of poles.
Note that different types of encoders (e.g., optical encoders, magnetic encoders, rotary encoders, etc.) may have different methods of determining the number of poles. Always consult the relevant specifications and documentation to ensure that the number of poles of the encoder is accurately determined before proceeding with any operation.
Introduction to relevant encoder magnets;
Why is four pairs pole magnet placed on the encoder?