Absolute Rotary Encoder Substitute！

If overall system simplicity matters more than performance, then there are alternatives to absolute encoders.
Resolvers
Resolvers are electro-mechanical precursors to encoders, based on technology going back to World War II. An electrical current creates a magnetic field along a central winding. There are two windings that are perpendicular to each other. One winding is fixed in place, and the other moves as the object moves. The changes in the strength and location of the two interacting magnetic fields allow the resolver to determine the motion of the object.

The simplicity of the resolver design makes it reliable in even extreme conditions, from cold and hot temperature ranges to radiation exposure, and even mechanical interference from vibration and shock. However, the forgiving nature of resolvers for both origin and application assembly comes at the expense of their ability to work in complex application designs because it cannot produce data with enough accuracy. Unlike absolute encoders, resolvers only output analog data, which can require specialized electronics to connect with.

Incremental Encoders
An incremental encoder determines relative position, looking only at the differences between measurements. The encoder engine sends out pulses in channels (called quadratures) and the offsets in these pulses indicate motion.

Incremental encoders provide excellent speed and distance feedback and, since there are few sensors involved, the systems are both simple and inexpensive. However, incremental encoders are susceptible to environmental factors like vibration (something that is mitigated as sensor technology improves), and they can lose resolution at high speeds due to output frequency limitations. They are also limited by only providing change information, so the encoder requires a reference device to calculate motion.

Previous：Roundss DC5V servo motor encoder ip50 optical sensor
Next：Roundss Manual Machine Tool Linear Encoder Optical Scale