An encoder is a device that compiles and converts signals (such as bitstreams) or data into signal forms that can be used for communication, transmission, and storage. Convert the angular displacement or linear displacement of the encoder into an electrical signal, the former is called a code wheel, and the latter is called a code ruler. Encoders that follow the reading mode can include contact and non-contact types; Following this working principle, encoders can include incremental and absolute encoders.. Then, let's patiently introduce the principle of the electric vehicle encoder to our friends.

Introduction to Encoder Knowledge - Working Principle

From an axis centered photoelectric encoder with circular on/off and dark lines, four sets of sine wave signals are obtained by reading from the photoelectric transmitter and receiver, and combined into A, B, C, and D. Each sine wave has a phase difference of 90 degrees (360 degrees compared to one cycle). By reversing the C and D signals and superimposing them on the A and B phases, the stability of the signal can be improved. Each revolution outputs another z-phase pulse, representing the zero reference position.

Due to the phase difference of 90 degrees between A and B, the forward and reverse directions of the encoder can be determined by comparing A and B phases, and the zero reference position of the encoder can be obtained by zero pulse. The materials of the encoder disk are glass, metal, and plastic. A glass disk is a thin line deposited on glass, with good thermal stability and high accuracy. The metal disc can be directly marked or not marked, and is not fragile. However, due to the necessary thickness and limited accuracy of metals, their thermal stability needs to be one order of magnitude worse than glass. Plastic discs are economical and cost-effective, but they require poor precision, thermal stability, and service life.

resolving power&The number of visible or hidden lines provided by the encoder for each 360 degree rotation is called resolution, also known as resolution division, or more or less direct lines, mostly ranging from 5 to 1000 lines per rotation.

Introduction to Encoder Knowledge - Installation and Use

Mechanical installation and use of absolute rotary encoders;

The mechanical installation of absolute rotary encoders includes high-speed end installation and low-speed end installation.

Installation of workshop auxiliary mechanical equipment and other forms.

High speed end installation: Installed at the shaft end (or gear connection) of the power motor. The advantage of this method is high resolution, as the multi turn encoder has 4096 turns, and the number of turns of the motor is within this range, which can fully utilize the full range to improve resolution. The disadvantage is that there is a gear clearance error after the moving object passes through the reduction gear, which is often used for one-way high-precision adjustment positioning, such as roll gap adjustment in steel rolling. In addition, the encoder is directly installed at the high-speed end, and the vibration of the motor must be small, otherwise it is easy to damage the encoder.

Low speed end installation: Installed behind the reduction gear, such as the shaft end of the winding wire rope drum or the last reduction gear shaft end. This method has no gear backlash, direct measurement, and high accuracy. This method mostly measures long-distance positioning, such as the positioning of various lifting equipment and feeding carts.

Installation of auxiliary machinery:

Commonly used ones include gears and racks, chain belts, friction wheels, rope winding machinery, etc.

Introduction to Encoder Knowledge - Wiring Method

A rotary encoder is a photoelectric rotary measuring device that directly converts the measured angular displacement into a digital signal (high-speed pulse signal).

If encoders are divided according to signal principles, there are incremental encoders and absolute encoders.

Generally, an incremental encoder is used, which can directly input the output pulse signal of the rotary encoder into the PLC, and count the pulse signal with the help of the PLC's high-speed counter to obtain the measurement result. Different types of rotary encoders may not necessarily have the same number of output pulses. Some rotary encoders output three-phase pulses of A, B, and Z, some only have A and B phases, and the simplest only has A phase.

The encoder has five leads, including three pulse output lines, one COM terminal line, and one power line (OC gate output type). The power supply of the encoder can be an external power supply or directly use the DC24V power supply of the PLC. Power Supply&ldquo-&rdquo； The terminal needs to be connected to the COM terminal of the encoder.

And connect it to the power supply terminal of the encoder. The communication terminal of the encoder is connected to the communication terminal of the PLC input. A. The B and Z two-phase pulse output lines are directly connected to the input terminal of the PLC. A and B are pulses that differ by 90 degrees. When the encoder rotates once, the Z signal has only one pulse. Usually used as a basis for zero point. When connecting, pay attention to the response time of PLC input. The rotary encoder also has shielded wires that need to be grounded to improve anti-interference performance.

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