Rotary encoder resolution changes2021

Rotary encoders are widely used in the field of industrial control. Designers will pay attention to the problem of encoder resolution when selecting models. What is the significance of the resolution of the encoder? Today we will learn to pay attention to the resolution of the encoder. How to determine the resolution of the encoder?

Resolution CPR is the name of the unit used on the encoder. It is a parameter of the encoder. CPR is the number of rotations per unit resolution.

We know that there are several types of encoders, and the resolutions of different models are different. In layman's terms, the resolution of an encoder is how many signals are output in one revolution. The accuracy of this turntable's rotation is the encoder. The resolution, that is, the accuracy of linear displacement measurement, the resolution of the encoder, can control the accuracy of the machine more accurately and the performance of the servo motor, so that the performance of the encoder can be better optimized, so the size of the resolution is the encoder A very important performance.

Pay attention to changes in encoder resolution

The encoder is composed of many grating lines. There are two or four optical eyes to read the A and B signals. The line density determines the resolution of the incremental encoder, and the smallest change angle can also distinguish the read value. The parameter indicating the resolution of the incremental encoder is PPR, that is, the number of pulses per revolution, for example, 360 lines per circle per line, A and B output of pulse pulses, the resolution parameter is 360PPR. What is the minimum angle change of the encoder? There are generally two types of A/B encoder output waveforms, one is a steep rising edge, a sharp fall along the square wave signal, a slow rise and fall, the output waveform of the Sin/Cos curve waveform signal is similar to a sine curve, A and B It is a 90 degree phase of 1/4T period. If A is a sinusoidal curve of Sin and B is a cosine curve of Cos, the phase difference of square wave signal A and B is 90 degree phase (1/4T), so at a phase angle of 0 degree, 90 Degrees, 180 degrees, 270 degrees phase angle, four rising and falling, so you can actually see the view of the 1/4T period change of the square wave, such as 1/4 T period is the minimum measurement distance, the rising edge of the circuit And the judgment of the falling edge can be 4 times the PPR reading angle change, which is the square wave frequency 4. This judgment can also be made by logic. 0 represents low and the other represents high. The changes of phase A/B in a cycle are 00, 01, 11, 10. This judgment can be not only 4 times, but also to determine the direction of rotation. Then, the minimum resolution angle of the square wave signal = 360 degrees/(4xPPR). The previous question: Square wave A/B output 360PPR incremental encoder, minimum resolution angle = 0.25 degrees. After the encoder output section A/B/Z square wave, it can also be repeated 4 times, but please note that the subdivision requirements of the encoder speed are generally lower. In addition, if the accuracy of the original marking is not high, the waveform is not perfect, or the circuit itself is broken down, the fault may be serious waveform distortion, step size, missing step, etc., selection and use need to pay attention.

How to determine the resolution of the encoder?

The resolution of the encoder is calculated according to the pulse. The basic pulse required by the motor is not less than 2500. The resolution represents the accuracy of the encoder. Therefore, the higher the pulse, the higher the resolution. After the encoder inputs the signal, it needs to perform several times the frequency processing, so the resolution can be improved to a certain extent. After the resolution is output and the code, there will be a phase difference between each code, and we can know through the phase difference The positive and negative sides of the motor in the machine, so that the resolution of the encoder can be known through each encoded pulse.

In addition, if you know how the pulse of the encoder is formed, you can also see the resolution of the encoder, then you have to observe the encoder's marking parameters and arrangement rules, and the width of the markings should be the distance between them. Equally, a general encoder has four identical grating lines, which can detect the process of waveform formation, and each waveform can detect the signal strength of the encoder, that is, the sine waveform of the encoder.

In summary, the resolution of the encoder is a parameter that represents the accuracy of the encoder. It is accurately calculated by the machine device. After the principle of pulse formation, the resolution is fully displayed, so whether you are buying When the encoder is still using the encoder, the resolution of the encoder must be considered.