What is an encoder

An encoder is a device that compiles converts a signal (such as a bit stream) data into a signal form that can be used for communication, transmission, storage. The encoder converts angular displacement linear displacement into electrical signals. The former is called a yardstick, the latter is called a yardstick. Encoders are divided into two types: contact type non-contact type according to read write modes, two types, incremental type absolute type, according to the working principle.

The incremental encoder converts the displacement into a periodic electric signal, then converts the electric signal into a counting pulse. The number of pulses represents the magnitude of the displacement. Each position of the absolute encoder corresponds to a digital code, so its indication is only related to the start end positions of the measurement, to the middle process of the measurement.

Encoder classification

According to the detection principle, encoders can be divided into optical encoders, magnetic encoders, inductive encoders capacitive encoders. According to its scaling method signal output form, it can be divided into incremental type, absolute type mixed type.

1 Incremental encoder:

The incremental encoder directly uses the photoelectric conversion principle to output three sets of square wave pulses A, B, Z phases; A B two sets of pulses are 90 degrees apart, which is convenient for judging the direction of rotation. Each revolution of the Z phase uses a pulse as a reference point Positioning. Its advantages are simple structure, average mechanical life of more than tens of thousands of hours, strong anti-interference ability, high reliability, suitable for long-distance transmission. The disadvantage is that the absolute position information of the shaft rotation cannot be output.

2 Absolute encoder:

The absolute encoder is a sensor that directly outputs numbers. There are multiple concentric code discs along the radial direction on the circular code disc. Each track is composed of transparent opaque parts. Fans of adjacent code channels double the relationship between trees in that area. The number of code channels on the code wheel is a binary number. One side of the code wheel is the light source, the other side is the photosensitive element corresponding to each code stream channel. When the code disc is in different positions, each photosensitive element converts the corresponding level signal to form a binary number according to whether it receives light. The feature of this encoder is that it does require a counter can read a fixed digital code corresponding to the position at any position of the axis. Obviously, there must be N kinds of theories. At present, there are 16-bit absolute encoder products in China.

three. Hybrid absolute encoder:

The hybrid absolute encoder outputs two sets of information. One set of information is used to detect the position has the function of absolute information; the other set of information is exactly the same as the output information of the incremental encoder.

2 Application of photoelectric encoder

The difference between incremental encoder absolute encoder

1 Angle measurement

In the car driving simulator, the photoelectric encoder is selected as the sensor for steering wheel angle measurement. The gravity measuring instrument uses a photoelectric encoder to connect its shaft to the compensation knob shaft of the gravity measuring instrument. The torsion angle meter uses an encoder to measure the change of the torsion angle, such as torsion testing machine, fishing rod torsion fishing performance test, etc.; the pendulum impact testing machine uses an encoder to calculate the impact is the change of the swing angle.

2 length measurement

The meter counter uses the circumference of the roller to measure the length distance of an object.

The cable displacement sensor uses the circumference of the reel to measure the length of the object.

Direct coupling measurement, a power device that drives linear displacement coupled with the main shaft, measures the number of output pulses.

In media detection, linear displacement information is transmitted through linear racks, rotating sprocket wheels, timing belt wheels.

three. Speed measurement

Line speed, connect the meter to measure the line speed of the production line

Angular speed, measure the speed of motors, shafts, etc. through encoders

4 position measurement

On the machine tool, the coordinate position of each coordinate point of the machine tool is stored, such as a drilling machine.

In terms of automatic control, it controls the designated actions of the pastoral area. Such as elevators, elevators, etc.

5 Synchronous control

Synchronous control transfer

DEUPREE (Qingdao) Industrial Technology Co., Ltd. is an integrated enterprise focusing on the research development of automated industrial technology equipment manufacturing. The company’s products mainly include rotational motion sensors, linear displacement sensors, object recognition sensors, laser rangefinders, process Control measurement instruments, signal detection systems, signal transmission systems, immature drive systems, UPS safety power supply systems, automation equipment energy-saving cleaning auxiliary equipment systems are limited to this. We can also customize flexibly customize according to customer needs. Meet the different needs of different customers.