Overview of Encoder

If you are in the mechanical industry, it will not be strange to you about the concept of what an Encoder is? Encoder is a device used in many automation industries. It is also an important part in the structure diagram of CNC machines. You will find Encoders used in cutting applications, plotters and more. You may have never noticed it, but Encoder is always there. However, not everyone clearly understands what an Encoder is? Application of Encoder, how does it work? Is there one type of encoder or many types? Let's find out everything you need to know about Encoder!

What is an encoder?

• An encoder, also known as an encoder, is a mechanical motion sensor that generates a digital signal in response to movement. Is an electromechanical device capable of converting motion into digital signals or pulses.
• The Encoder is a very important part in the structure of the CNC machine. It helps measure and display machine speed parameters.
• There are two types of encoders: linear and rotary. Linear encoders respond to motion along a path, while rotary encoders respond to rotational motion.

What are the basic types of Encoder?

The encoder is used to manage the angular position of a rotating disc, which can be a wheel disc, a motor shaft or any other device that needs to determine the angular position.

An encoder is often classified according to its output means, including two main types: Absolute Encoder and Relative Encoder.

• Absolute encoder

– Absolute encoder (adsolute encoder): When called absolute, it means that the signal we receive from the Encoder indicates the exact position of the Encoder without the user having to process anything further.

+ Use disk according to binary code or Gray code.

+ Has a structure including: a light emitter (LED), an encoding disk (containing a signal-carrying tape), a light receiver sensitive to the emitted light.

+ The encoder disk in Encoder is made from transparent material, the disk surface is divided into equal angles with concentric circles.

+ Advantage: retains absolute value when Encoder loses power.

+ Defect: high cost because of complex manufacturing and difficult to read signals.

• Relative encoder

– Relative encoder (incremental encoder): emits signals gradually or periodically

+ The encoder disk consists of a strip of pulse-generating tape, usually divided into many equal and evenly spaced holes.

+ The material can be transparent to help light shine through.

+ Encoder has only 1,2 or maximum 3 hole rings, and usually has an additional positioning hole.

+ Advantage: low cost, simple manufacturing, easy processing of returned signals.

+ Defect: susceptible to pulse error when returned. Errors will accumulate during long-term operation.

Structure of Encoder

Encoders include:

• 1 rotating disc with holes attached to the motor shaft.
• 1 LED lamp is used as a light source.
• 1 photoelectric receiver is arranged in a straight line.
• The circuit board helps amplify the signal.

What is the operating principle of the Encoder?

• When the Encoder moves, the converter will process the movements and convert them into electrical signals. These signals will be transmitted to PLC control devices and processed to represent the values to be measured using a separate program.
• For signals with or without light shining through. People can still record whether the LED light shines through this hole or not. Furthermore, the number of pulses counted and increased is calculated by the number of times the light is cut off.
• For example, on a disc there is a single hole. Each time the eye receives an LED signal, it means the disc has rotated 1 revolution.
• Therefore, this is the basic operating principle of the Encoder, but for many other types of Encoder, when the rotating disc has more holes, the received signal will be different.

Where is the Encoder application?

Encoder becomes an important source for many applications. Whether related to speed, direction or distance, the Encoder's capabilities allow the user to use this information for precise control.

• Application of speed expression

When a pump is connected to an inverter to pump liquid into a tank. Then the liquid flowing into the tank must have a certain speed. The encoder connected to the inverter will respond to the actual flow rate of the liquid.

• Measurement applications

When we need to cut aluminum coils hundreds or thousands of meters long into panels of a certain size through a cutting machine. The Encoder will then be installed on the conveyor belt, reading the material each time it passes through the Encoder and calculating the length of the aluminum sheet from the time it is inserted to the cutting position. The cutting knife can be adjusted to the required length through the aluminum sheet size parameters.

• Application for counting numbers

Installing Encoder into the program of product conveyors. It will help us confirm each bottle of product entering and station on the conveyor belt. If the bottles do not leave the station within the programmed time and do not correspond to the value counted by the Encoder. It also means that the machine has been damaged.

• Application of Encoder in mechanical industry

Talking about the structure of CNC machines, the Encoder is equipped as a device to help measure and determine the most accurate position of the machine axes as well as the position where the knife cuts. Therefore, when using CNC machines for processing, you will achieve the most accuracy. Furthermore, the information recorded by the Encoder will be reported to the PLC control system. From there, the user can adjust the knife cutting position to limit errors.

• Applications in industries

+ Cars

In the automotive industry, encoders are used as mechanical motion sensors, which can be applied to speed control.

+ Consumer electronics and office equipment:

Encoders are used as PC-based devices, printers and scanners.

+ Industry:

Encoders are used in labeling, packaging and machine making with single and multi-axis motor controls.

+ Medical:

Encoders are used in medical scanners, microscopic or nanoscopic motion control of automated devices and dispensing pumps.

+ Army:

Encoders are used in positioning antenna applications.

+ Scientific instruments:

Scientific equipment implements encoders in the positioning of observing telescopes.

Customers have needs  Encoder  xPlease contact us immediately for advice and answers.

Trading & Joint Stock Company HBS Services Vietnam

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