In short, an encoder is a sensing device that provides feedback. An encoder converts motion into electrical signals and can read signals from certain control devices in a motion control system, such as counters or PLCs. The encoder sends feedback signals that can be used to determine position, count, speed, or direction. This information can then be used to send commands for specific functions. The earliest encoders on the market were primarily resolvers. A rotary transformer is an electromagnetic sensor, also known as a synchronous rotary transformer. It is a small AC motor that measures angles, used to measure the angular displacement and angular velocity of a rotating object. It consists of a stator and a rotor. The stator windings, as the primary side of the transformer, receive the excitation voltage, typically at frequencies of 400, 3000, and 5000 Hz. The rotor windings, as the secondary side of the transformer, obtain the induced voltage through electromagnetic coupling. What are the functions and usage methods of an encoder?
1. Function of the encoder
The speed of a motor can be obtained through an encoder. The main principle is that the encoder can obtain the motor's rotation speed based on the number of output pulses and the number of counted pulses.
Encoder signals (such as bitstreams: BitTorrent) are a content distribution protocol. It uses efficient software distribution systems and peer-to-peer technology to share large files (such as movies or TV shows) and allows each user to contribute upload services, like a network redistribution point. General download servers provide download services to users who send download requests. BitTorrent works differently. The distributor or file holder sends the file to one user, who then forwards it to other users. Users forward their portions of the file to each other until each user's download is complete. This method allows download servers to handle multiple large file download requests simultaneously using significant bandwidth. Bitstreams are known as the "cluster, scatter, cluster" file transfer protocol for bitstreams. It was written by programmer Bram Cohen using Python. It is also open-source proprietary software that can be downloaded and distributed free of charge. (A device that prepares data, converts it into usable communication, transmits and stores data in the form of signals.)
2. How to use an encoder
An encoder converts angular or linear displacement into electrical signals. The former is called a code disk, and the latter a ruler. Encoders use different types of techniques to create signals, including mechanical, magnetic, resistive, and optical signals. In optical sensors, the encoder provides feedback based on interruptions in light. The figure below illustrates the basic structure of an incremental rotary encoder using optical techniques.
An LED beam passes through a code disk with opaque lines (much like spokes on a bicycle wheel). As the encoder shaft rotates, the beam from the LED is interrupted by the opaque lines on the disk and then picked up by a photodetector assembly. This generates a pulse signal: one LED on the disk = on; no LED = off. The signal is sent to a counter or controller, which then sends a signal to produce the desired function.
3. Encoder Function
Based on the reading method, common encoders can be divided into contact and non-contact types; based on their working principle, encoders can be divided into incremental encoders and absolute encoders. We will now focus on incremental and absolute encoders:
Incremental encoders convert displacement into periodic electrical signals, which are then converted into counting pulses. The number of pulses represents the displacement. Absolute encoders, on the other hand, assign a specific digital code to each position, so their indication depends only on the start and end positions of the measurement, and not on the intermediate steps.
An encoder? In short, an encoder can generate incremental or absolute signals. An incremental signal does not indicate a specific position, but only that the position has changed. On the other hand, an absolute encoder uses different position "words," meaning that an absolute encoder provides not only an indication of position change, but also an indication of absolute position.
