How does an encoder work?

By a photoelectric code disc with an axis in the center, there is a ring through and a dark engraved line on it, and a photoelectric transmitting and receiving device reads it, and obtains four groups of sine wave signals combined into A, B, C, D, each sine wave is 90 degrees apart by a phase difference (360 degrees relative to a cycle), the C and D signals are reversed, and superimposed on the two phases of A and B, which can enhance the stable signal; A z-phase pulse is also output per revolution to represent the zero reference bit.

Since the difference between phase A and phase B is 90 degrees, the forward and reverse rotation of the encoder can be determined by comparing phase A in front or phase B in front, and the zero reference bit of the encoder can be obtained through the zero pulse.

An optical encoder is a sensor that converts the mechanical geometric displacement on the output shaft into pulses or digital quantities through photoelectric conversion. The optical encoder outputs 600 pulses per revolution (we didn't say what the boss said), five-wire system. Two of them are power lines and three are pulse lines (phase A, phase B, and Z).

The power supply operates from a DC power supply of (+5 +24V). The optical encoder is composed of a grating disc and a photoelectric detection device. The grating disc is to open a number of rectangular holes in equal parts on a circular plate of a certain diameter.

Because the photoelectric code disc is coaxial with the motor, when the motor rotates, the grating disc rotates at the same speed with the motor, and a number of pulse signals are detected and output by the detection device composed of electronic components such as light-emitting diodes, and the schematic diagram of its principle is shown in Figure 1; By calculating the number of pulses output by the optical encoder per second, the speed of the current motor can be reflected. In addition, in order to determine the direction of rotation, the disc can also provide two pulse signals with a phase difference of 90 0 2.

Working principle: When the axis of the photoelectric encoder rotates, the two lines of A and B produce pulse output, and the phase angle of the two phases of A and B is 90 degrees, so that the rotation direction of the photoelectric encoder and the motor speed can be measured. If the A phase pulse is ahead of the B phase pulse, the optical encoder is forward, otherwise it is reversed.

The z-line is a zero-pulse line, and the photoelectric encoder generates a pulse per revolution. It is mainly used as a count. The A line is used to measure the number of pulses, and the B line and A line can be used to measure the direction of rotation.

n is the speed of the motor.

n = nd test - nd reason.

For example: the speed of our car is, the diameter of the wheel is 220mm, c = d * pi, the motor is controlled in the revolution, according to the index of the servo system, the motor speed is set to 1500 revolutions, so it can be obtained when nd = revolution, the number of pulses output by the optical code disc per second is:

PD = 130 600 60 = 1300 pulses.

When there is a deviation between the measured number of pulses and the calculated standard value, the incremental voltage U output to the servo system can be calculated according to the correspondence between the voltage and the number of pulses, and then the number of incremental pulses is calculated after D a conversion, and so on.

When the running time is longer, the longer the route, the more deviations from our prefabricated route. At this time, the system starts the position loop, by continuously measuring the number of pulses output by the photoelectric encoder per second, and comparing it with the standard value PD (ideal value), calculating the increment p and converting it into the corresponding D a output digital quantity, reducing the number of pulses of the motor through the controller, subtracting the increment on the basis of the original output voltage, forcing the motor speed to decrease, and stopping the adjustment when the measured p is approximately zero, so that the motor speed can always be controlled within the allowable range.

The encoder has a photoelectric code disc with an axis in the center, the photoelectric code disc contains a ring through, dark engraved line, the scale value is read by the photoelectric transmitter and the photoelectric receiver, and four groups of sine wave signals (a, b, c, d) are read, and each sine wave phase difference is 90 degrees, that is, the period is 360 degrees. The two sine wave signals C and D are reproduced and superimposed on A and B, which can be used to enhance the stable signal. In addition, a z-phase pulse is output per revolution to represent the zero reference bit. Since the phase difference between the two sine waves A and B is 90 degrees, the encoder can be judged whether the encoder is forward or reverse by comparing the positions of the two sine waves A and B. The zero reference bit of the encoder can be obtained by means of a zero pulse.

An encoder, or encoder, is a device that converts signals in the form of a signal. The encoder converts angular or linear displacement into an electrical signal, which we call a code disc and a yardstick. Encoders can be divided into incremental encoders and absolute encoders according to their working principles.

Among them, the incremental encoder first converts the displacement into a periodic electrical signal, then converts the electrical signal into a counting pulse, and finally uses the number of pulses to express the size of the displacement. Absolute encoders, on the other hand, correspond to a defined digital code at each position, and the final result is only related to the start and end points of the measurement, not to the intermediate process.

Summary. The function of an encoder is as follows: An encoder is a rotary sensor that converts rotational displacement into a series of digital pulse signals.

These pulses can be used to control angular displacement. If the encoder is combined with a gear rod or screw, it can also be used to measure linear displacement. The electrical signals generated by the encoder are processed by the CNC control, the programmable logic controller PLC and the control system.

These sensors are mainly used in the following areas: machine tools, material processing, motor feedback systems, and measurement and control equipment. Eltra encoders use the principle of photoelectric scanning for angular displacement conversion.

This reading system is based on the rotation of a radial dial consisting of alternating transparent and opaque windows. The system is illuminated vertically by an infrared light source, which projects the image on the disc onto the surface of the receiver, which is covered with a grating called a collimator, which has the same window as the disc. The receiver's job is to sense the change in light caused by the rotation of the disc, and then convert the change in light into the corresponding electrical change.

Generally, the rotary encoder can also get a speed signal, which should be fed back to the inverter and adjust the output data of the inverter.

The function of an encoder is as follows: An encoder is a rotary sensor that converts rotational displacement into a series of digital pulse signals. These pulses can be used to control angular displacement.

If the encoder is combined with a gear rod or screw, it can also be used to measure linear displacement. The electrical signals generated by the encoder are processed by the CNC control, the programmable logic controller PLC and the control system. These sensors are mainly used in the following areas:

Machine tools, material processing, motor feedback systems and measurement and control equipment. Eltra encoders use the principle of photoelectric scanning for angular displacement conversion. This reading system is based on the rotation of a radial dial consisting of alternating transparent and opaque windows.

The system is illuminated vertically by an infrared light source, so that the light vertically projects the image on the disc onto the surface of the receiver, which is covered with a grating called a collimator, with the same window as the disc. The receiver's job is to sense the change in light caused by the rotation of the disc, and then convert the change in light into the corresponding electrical change. Generally, the rotary encoder can also get a speed deficit signal, which should be fed back to the inverter and adjust the output data of the inverter.

In the case of incremental encoders, the position is determined by the number of pulses calculated by the zero mark, while the position of the absolute encoder is determined by the reading of the output code. In a circle, the reading of the output code is unique for each position; As a result, the absolute encoder does not detach from the actual position next to the group when the power is turned off.

If the power is turned on again, the position reading is still valid; Unlike incremental encoders, you have to go to YoYo to find change. At present, encoder manufacturers produce a full range of encoders, which are generally special, such as special encoders for elevators, special encoders for machine tools, special encoders for servo motors, etc. And the encoder is both consumer or wax intelligent, with a variety of parallel interfaces, can communicate with other devices.

How an encoder works: It is a rotary sensor that converts rotational displacement into a series of digital pulse signals that can be used to control angular displacement and, if the encoder is combined with a gear bar or spiral screw, can also be used to measure linear displacement.

According to the working principle, encoders can be divided into two types: incremental and absolute. The incremental encoder converts the displacement into a periodic electrical signal, and then converts the electrical signal into a counting pulse, and the number of pulses indicates the size of the displacement. Each position of an absolute encoder corresponds to a defined digital code, so its indication is only relevant to the start and end positions of the measurement, and not to the intermediate process of the measurement.

An encoder switch is a type of switch that can control a device for a specific operation. Common uses include ampement, pitch and volume control for audio devices, screen brightness and contrast adjustment for electronic devices, and more.

When using an encoder switch, it needs to be rotated or pressed to adjust the set.

Rotary encoders are mainly used to control the rotation parameters of the device, such as the volume of the audio device, etc. It usually consists of a large knob and a dial that controls the amplitude of rotation. The user can control the operation of the device by means of a knob, and then determine the specific settings according to the markings on the dial.

The encoder switch is a very convenient and practical switch that can help users easily control the functions of various electronic devices.

The working principle of the encoder is to obtain four sets of sine wave signals to be combined into A, B, C, D by a photoelectric code disc with an axis in the center, on which there are annular through and dark engraved lines, and a photoelectric transmitting and receiving device reads them. The forward and reverse rotation of the encoder can be determined by comparing the A phase in front or the B phase in front, and the zero reference bit of the encoder can be obtained by the zero pulse.

The material of the encoder code disc is glass, metal, plastic transport vertical shouting material, the glass code disc is deposited on the glass very thin engraved line, its thermal stability is good, high precision, the metal code disc is directly through and not through the engraved line, not fragile, but because the metal has a certain thickness, the accuracy is limited, its thermal stability is an order of magnitude worse than the glass, the plastic code disc is economical, its cost is low, but the accuracy, thermal stability, life are poor.

Resolution—The encoder is called resolution by how many through or dark lines are provided per 360 degrees of rotation, also known as the resolution index, or directly how many lines are weighed, generally at 5 10,000 lines per revolution.