Pulse encoder Principle and Application！

Pulse encoder Principle and Application
    

  Pulse encoder is a rotary pulse generator, the mechanical angle into electrical impulses, is a common angular displacement sensor. Also can be used for speed detection devices.

 Classification and structure of pulse encoder

    Divided photoelectric encoder, contact and electromagnetic induction type three. Optical precision and reliability are better than the other two, so use only photoelectric pulse encoder on CNC machine tools.

    Photoelectric pulse encoder structure shown in Figure 4-16. On the circumference of a disc engraved with equally spaced lined, divided into transparent and opaque sections, called circular grating. Rotates together with the operating shaft angle encoder. Circle gratings, placed parallel to a stationary fan-shaped sheet, called index grating, the above system has shifted by 1/4 pitch two slits (slits resolution). In addition, there is a zero slot (one pulse per revolution). Pulse generator connector or bond servo motor connected via cross.

  (Ii) the working principle of pulse encoder

    When rotated together with the operating shaft angle encoder, the light through the lined portion of the two gratings to form light and dark stripes. Optoelectronics accept these light and dark optical signal, and converted to electrical signals of alternating. The electrical signal is approximately sinusoidal current signal groups A and B, shown in Figure 4-17. A and B signals out of phase 90 °, amplified and shaped into a square wave. By signals from the two gratings, there is a "pulses per revolution", known as Z-phase pulse, which is processed by the above come. Z pulse is used to generate the machine reference point. Later pulse is supplied to the counter, according to the number and frequency of the pulses can be measured angle and speed work shaft. Its resolution depends on the number of turns of multiple segments and measuring lines round grating.

(Iii) the application of optical pulse encoder

    Optical pulse encoder on CNC machine tools used for position detection device, the detection signal is fed back to the CNC system. Its feedback to the numerical control system in two ways: First, to adapt to the requirements with the addition and subtraction count down counter, pulse counting is formed and down counting pulses; the second is to adapt the control and counting requirements have counted counter direction of formation of the control signal pulse counting .

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