Remerciez-le!

Remerciez @Admin pour avoir partagé cet document gratuitement, de la manière la plus simple, en partageant sur les réseaux sociaux.

Design guide Encoder Design Guide Optical Encoder Incremental Encoders The incremental encoder creates a series of square waves The number of square waves can be made to correspond to the mechanical increment required For example to divide a shaft revolut

Encoder Design Guide Optical Encoder Incremental Encoders The incremental encoder creates a series of square waves The number of square waves can be made to correspond to the mechanical increment required For example to divide a shaft revolution into parts an encoder could be selected to supply square wave cycles per revolution By using a counter to count those cycles we could tell how far the shaft rotated counts would equal degrees counts degrees etc The number of cycles per revolution is limited by physical line spacing and quality of light transmission We provide incremental resolutions up to counts per turn through a combination of direct read on the code disc and various multiplication techniques see count multiplication on next page Generally incremental encoders provide more resolution at a lower cost than their absolute encoder cousins They also have a simpler interface because they have fewer output lines Typically an incremental encoder would have lines quadrature A B signals and power and ground lines A bit absolute encoder by contrast would require output wires plus a power and ground line Any Questions Call - -ENCODER and ask for ??Applications Assistance ? Electronics Board Photodetector Assembly Mask Light Source Bearing Housing Assembly Code Disc CDesign and Operation Absolute Encoders An absolute encoder provides a ??whole word ? output with a unique code pattern representing each position This code is derived from independent tracks on the encoder disc corresponding to individual photodetectors The output from these detectors would then be HI or LO depending on the code disc pattern for that particular position Absolute encoders are used in applications where a device is inactive for long periods of time or moves at a slow rate such as ood gate control telescopes cranes valves etc Count Multiplication Bit Absolute Disc Disc Pattern Photodetectors Output Light Source Count Multiplication Incremental encoders are often supplied with two channels A B that are o ?set from one another by of a cycle degrees This type of signal is referred to as quadrature and allows the user to determine not only the speed of rotation but its direction as well By examining the phase relationship between the A and B channels one can determine if the encoder is turning clockwise B leads A or counterclockwise A leads B Many counter and controller manufacturers include a quadrature detection circuit as part of their electronics This allows the use of a two-channel quadrature input without further conditioning With quadrature detection we have the ability to derive X X or X the basic code disc resolution counts per turn can be generated from a cycle two-channel encoder by detecting the Up and Down transitions on both the A and B channels With a quality disc and properly phased encoder this X signal will be accurate to better than count Another type of count multiplication interpolation can be used to electronically subdivide the base resolution Interpolation is achieved through the use of internal electronics and results in improved resolution This interpolated