How to use an encoder for accurate speed measurement? In terms of encoder usage, angle or straight-line distance measurement is an important aspect, and can also be used for speed or linear velocity measurement. When the encoder rotates faster, the pulse frequency increases at the same rate.

The encoder measurement speed can be determined by either of two methods: pulse counting or pulse timing.

Incremental encoders typically output signals on two channels - commonly referred to as "A" and "B" - offset by 90 degrees between the two phases. The direction of rotation can be determined by which channel comes forward. Normally, if channel A is ahead, the direction is clockwise, and if channel B is ahead, the direction is counterclockwise. Orthogonal output also allows for increasing the resolution of the encoder by using X2 or X4 decoding techniques. When decoding X2, both the rising and falling edges of channel A are counted, doubling the number of pulses counted per revolution, thus doubling the resolution of the encoder. Using X4 decoding, the rising and falling edges of channels A and B will be counted along the river, thereby increasing the resolution by four times.

Encoder speed measurement may be affected by various device errors, including instrument errors, phase errors, and interpolation errors.

Instrument errors include mechanical defects in the encoder and scale errors on the encoder disc or reticle. The errors related to the instrument include the flatness of the substrate, the accuracy of sensor positioning, and whether the concentricity between the encoder and motor shaft is consistent.

Phase error is caused by missing information transmission between pulses or readings. Orthogonal encoders only read the edges of signals on one or two channels (A and B) and do not transmit information between these readings. Phase error is only ± 1/2 or counting of a fixed measurement step.

Interpolation errors only occur when the encoder resolution exceeds the inherent X4 decoding electronic level of the orthogonal encoder. The interpolation error increases with the increase of encoder speed. Using encoders with higher row counts or more windows can reduce interpolation and phase errors.