Operating voltage: 5V

Number of pulses: 20

The rotary encoder can count the number of pulses output in the forward and reverse directions by rotation, and the rotation count is not like the potentiometer. This rotation count is not limited. With the key on the rotary encoder, you can reset to the initial state, that is, counting from 0.

working principle:

An incremental encoder is a rotary sensor that converts a rotary displacement into a series of digital pulse signals. These pulses are used to control the angular displacement. The conversion of the angular displacement in the Eltra encoder uses the principle of photoelectric scanning. The reading system is based on the rotation of the radial indexing disc (code disc) consisting of alternating light transmission windows and opacifying windows, and is irradiated vertically by an infrared light source, and the image of the code is projected onto the receiver surface The The receiver is covered with a layer of diffraction grating, which has the same window width as the encoder. The work of the receiver is to feel the changes that occur when the disc rotates, and then convert the light changes to the corresponding electrical changes. And then the low level signal to a higher level, and produce no interference with the square pulse, which must be used to deal with electronic circuits. The reading system usually uses a differential mode, which compares the two signals with the same waveform but with a phase difference of 180 ° in order to improve the quality and stability of the output signal. The readings are formed on the basis of the difference between the two signals, thus eliminating the interference.

Incremental Encoder:

Incremental encoders give two-phase square waves with a phase difference of 90 °, commonly referred to as A-channel and B-channel. One of the channels gives the speed-related information, at the same time, through the two channel signals in order to compare, get the direction of rotation information. There is also a special signal called Z or zero channel, which gives the absolute zero of the encoder, which is a square wave coinciding with the center line of the A channel square wave.

Incremental encoder accuracy depends on both mechanical and electrical factors such as grating indexing error, optical disc eccentricity, bearing eccentricity, error introduced by the electronic reading device, and imprecision of the optical section. The unit of measurement that determines the accuracy of the encoder is the electrical degree, and the encoder accuracy determines the pulse division of the encoder. The following shows the rotation of the mechanical shaft with a 360 ° electrical degree, and the rotation of the shaft must be a complete cycle. To know how much mechanical angle is equivalent to the electrical 360 degrees, you can use the following formula to calculate: Electric 360 = machine 360 ° / n ° pulse / turn

Figure: A, B commutation signal

The encoder indexing error is expressed as the maximum offset of two consecutive bursts of electrical angles. The error is present in any encoder, which is caused by the foregoing factors. The maximum error of the Eltra encoder is ± 25 electrical angle (under any condition that has been declared), corresponding to a nominal deviation of ± 7%, and the maximum deviation of the two channels with a phase difference of 90 ° (electrical) is ± 35 The electrical degree is equivalent to about ± 10% of the rated value.

UVW signal incremental encoder

In addition to the conventional encoders, there are some incremental encoders that are integrated with other electrical output signals. The incremental encoder integrated with the UVW signal is an example that is commonly used for feedback from AC servo motors. These magnetic pole signals generally appear in the AC servo motor, UVW signal is generally designed by simulating the function of the original magnetic. In Eltra encoders, these UVW signals are generated optically and appear in three square waves, which are offset from each other by 120 °. In order to facilitate the motor to start, control the starter for the motor needs these correct signals. These UVW pole pulses can be repeated many times in the mechanical axis rotation as they depend directly on the number of connected motor poles and are used for UVW signals of 4, 6 or more polar motors.