Commonly used encoder classification and all kinds of working principle of the encoder
Rotary encoder is one of the types of sensors, mainly played a testing mechanical movement speed, the effect of parameters such as position, Angle and distance.
As the encoder signal detection method has been widely applied in various industries.
Working principle of rotary encoder is this: when the rotary encoder shaft drives the rotating grating, light emitted by the luminous element is slit grating plate cutting into intermittent light, and by generating the initial signal receiving components.
The signal after the subsequent processing circuit, the output pulse signal or code.
Rotary encoder has the advantage of small volume, light weight, many varieties, full functions, high frequency response, high resolution, small torque, low consumption, stable performance, reliable service life is long.
Rotary encoder common types are incremental encoder, absolute encoder, sine wave encoder, what are the three encoder?
1, the incremental encoder shaft rotates, the incremental encoder with the corresponding phase output.
The direction of rotation of discrimination and pulse number of increase and decrease, need to use the sentence at the back of the circuit and the counter.
It can be set arbitrary starting point count and infinite accumulation and can realize the circle and measurement.
Can also turn each signal a pulse Z, mechanical zero as a reference.
When the pulse has been fixed, but need to improve resolution, available with 90 degree phase A, B two road signals, frequency doubling on the original pulse number.
2 absolute encoder, absolute encoder shaft rotator, one-to-one with position code (
Binary, BCD code, etc. )
Change in the output from the code size can distinguish positive and negative position, direction and displacement without sentenced to the circuit.
It has an absolute zero code, when a power outage or shutdown after the boot to measure, can still be accurately read a power outage or shutdown location code, and accurately find the zero code.
The general case of absolute encoder measuring range of 0 ~ 360 degrees, but special model also can realize more circle measurement.
3 sine wave, sine wave encoder encoder also belong to the incremental encoder, the main difference is that the output signal is a sine wave analog signals, rather than a digital signal.
It is mainly in order to meet the needs of the electric field -
Used as the feedback of the motor detecting element.
On the basis of compared with other systems, can be used when people need to improve the dynamic characteristics of the encoder.
So in practice and how to choose the rotary encoder?
In order to guarantee the performance of motor control, the encoder feedback signal must be able to provide a large number of pulses, especially at very low speed, the traditional incremental encoder to produce a large number of pulses, in many ways all have a problem, when the motor at high speed (
, transmission and processing of digital signal is difficult.
In this case, the signal processing to the servo motor, servo motor required bandwidth (
Encoder each turn pulse is 10000, for example)
Will easily exceed MHz threshold;
On the other hand the analog signal greatly reduce the trouble, and have the ability to simulate a large number of pulse encoder.
Thanks to the sine and cosine signal interpolation method, it provides a method to calculate the rotation Angle.
This method can obtain the fundamental sinusoidal high increase, for example, to transfer from every 1024 encoder sine wave, each turn more than 1000000 pulse.
Accept this as long as a little more than 100 KHZ or the bandwidth required of the signal is enough.
Interpolation frequency multiplication must be completed by the secondary system.
For users to choose the appropriate encoder performance is very important, we should understand the characteristics of various types of rotary encoder, to seek to use the appropriate encoder, Shanghai electronic products co. , LTD. , specializing in the production of rotary encoder, 25 years, relying on years of experience in research and development production, for customers and social consensus, is good rotary encoder manufacturer, welcome to contact us to discuss related business.