Understand the working principle of encoders and incremental encoders

In the field of industrial control, encoders are often used. What is encoding Device? How does it work? Today we will talk about editing this article

The working principle of the encoder and the detailed discussion of the incremental encoder.

Encoder|Transmitter|Soft starter|Power supply|VFD|Light curtain|Servo products|Human-machine interface|Solenoid valve|Cylinder|Actuator|Flow meter|Transformer|Thyristor|Sensor|Deceleration drive gearbox reducer|Linear guide|Circuit breaker|Refrigeration compressorAll industrial products of okplazas are purchased from the original factory or formal channels of agents to ensure the original authenticity, which perfectly solves the problem of industrial product sample procurement and small-batch procurement for the majority of engineers and purchasing personnel.

"Encoder" is a sensor that can convert distance (linear displacement) and angle (angular displacement) into electrical signals and output them.

Encoders are usually used in industrial motion control to measure and feedback the position and status of the measured object, such as machine tools, robots, motor feedback systems, and measurement and control equipment.

According to different working principles, encoders can be divided into optical encoders, magnetic encoders, inductive encoders and capacitive encoders, etc. The most used ones are Photoelectric encoder.

The composition of the optical encoder includes: Shaft, Code disk, LightSource, Output circuit, shell and connecting flange, etc., as shown in the following figure:

Encoder|Transmitter|Soft starter|Power supply|VFD|Light curtain|Servo products|Human-machine interface|Solenoid valve|Cylinder|Actuator|Flow meter|Transformer|Thyristor|Sensor|Deceleration drive gearbox reducer|Linear guide|Circuit breaker|Refrigeration compressorAll industrial products of okplazas are purchased from the original factory or formal channels of agents to ensure the original authenticity, which perfectly solves the problem of industrial product sample procurement and small-batch procurement for the majority of engineers and purchasing personnel.

The connecting shaft is connected to the code disc and connected to the measured object. As the measured object (such as a motor) rotates, the code disc also rotates. The light passing through the code disc will change between light and dark, and the photosensitive element at the receiving end will detect This change is converted into an electrical signal for output.

According to the difference of the code disc structure, the encoder can be divided into incremental encoder and absolute encoder. In this article, we mainly discuss incremental encoder.

Incremental encoder, the English name "Incremental encoder", its code disc is divided into light and dark gratings of equal size. As the code disc rotates, the receiving end will detect the change of light 0 and 1 and convert it into The electrical signal pulse is output externally. By counting the pulses, the magnitude of the displacement can be determined, as shown in the figure below:

Encoder|Transmitter|Soft starter|Power supply|VFD|Light curtain|Servo products|Human-machine interface|Solenoid valve|Cylinder|Actuator|Flow meter|Transformer|Thyristor|Sensor|Deceleration drive gearbox reducer|Linear guide|Circuit breaker|Refrigeration compressorAll industrial products of okplazas are purchased from the original factory or formal channels of agents to ensure the original authenticity, which perfectly solves the problem of industrial product sample procurement and small-batch procurement for the majority of engineers and purchasing personnel.

In order to distinguish between forward and reverse and to detect the zero point, the actual code disc used is more complicated than the above figure. It usually includes three parts: A phase, B phase and Z phase. A phase and B phase differ by 1/2 cycle (phase difference 90 Degree), can be used to distinguish between forward and reverse rotation; Z-phase is a single-turn pulse, which is generated once when the code wheel rotates once, and can be used as the reference zero of the encoder, as shown in the figure below:

Encoder|Transmitter|Soft starter|Power supply|VFD|Light curtain|Servo products|Human-machine interface|Solenoid valve|Cylinder|Actuator|Flow meter|Transformer|Thyristor|Sensor|Deceleration drive gearbox reducer|Linear guide|Circuit breaker|Refrigeration compressorAll industrial products of okplazas are purchased from the original factory or formal channels of agents to ensure the original authenticity, which perfectly solves the problem of industrial product sample procurement and small-batch procurement for the majority of engineers and purchasing personnel.

The output waveform of the incremental encoder is as follows:

Encoder|Transmitter|Soft starter|Power supply|VFD|Light curtain|Servo products|Human-machine interface|Solenoid valve|Cylinder|Actuator|Flow meter|Transformer|Thyristor|Sensor|Deceleration drive gearbox reducer|Linear guide|Circuit breaker|Refrigeration compressorAll industrial products of okplazas are purchased from the original factory or formal channels of agents to ensure the original authenticity, which perfectly solves the problem of industrial product sample procurement and small-batch procurement for the majority of engineers and purchasing personnel.

Due to the pulse counting method, the incremental encoder must first look for the reference zero before measuring, so its measurement results are relative. In addition, the data of incremental encoder will be lost after power failure.

In order to overcome the shortcomings of incremental encoders, absolute encoders came into being. We will introduce the relevant knowledge of absolute encoders in the next article.