Why Should An Encoder Be Installed On A Motor? How Does An Encoder Work?

Why should an encoder be installed on a motor?   How does an encoder work?

During the operation of the motor, real-time monitoring of current, speed, relative position of the circumferential direction of the shaft and other parameters, determine the motor body and the state of the dragged equipment, and further control the operation status of the motor and equipment in real time, so as to realize many specific functions such as servo and speed regulation. Here, the application of encoders as front-end measuring elements not only greatly simplifies the measuring system, but is also precise, reliable and powerful.

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The encoder is a rotary sensor that converts the position and displacement physical quantity of the rotating part into a series of digital pulse signals, which are collected and processed by the control system, and a series of instructions are issued to adjust and change the operating state of the equipment. If the encoder is combined with a gear strip or screw, it can also be used to measure the position, displacement of the physical quantity of the linear moving part.

Encoders are used in motor output signal feedback systems, measurement and control equipment. The encoder is composed of two parts: optical code disk and receiver, and the optical parameters generated by the rotation of the optical code disk are converted into corresponding electrical parameters, and the signal driving the power device is output through the pre-amplification and signal processing system in the inverter.

In general, a rotary encoder can only feed back a speed signal, compare it with the set value and feed it back to the actuator unit of the inverter, thereby adjusting the motor speed.

According to the detection principle, encoders can be divided into optical, magnetic, inductive and capacitive. According to its scale method and signal output form, it can be divided into three types: incremental, absolute and hybrid.

incremental encoders, the bits of which were determined from the number of pulses calculated from the zero mark; It is to convert the displacement into a periodic electrical signal: then convert this electrical signal into a counting pulse, and express the displacement by the number of pulses; The position of the absolute encoder is determined by the reading of the output code, and the output code reading at each position within a lap is unique, and the one-to-one correspondence with the actual position is not lost when the power supply is disconnected. Therefore, the incremental encoder is powered off and turned on again, and the position reading is current; Each position of an absolute encoder corresponds to a definite digital code, so its indicated value is only related to the start and end position of the measurement, and not to the intermediate process of the measurement.

As an information collection element for the operating status of the motor, the encoder is connected to the motor by mechanical installation, and in most cases it is necessary to add an encoder holder and termination shaft to the motor. In order to ensure the effectiveness and safety of motor operation and acquisition system operation, the coaxiality requirements of the encoder termination shaft and spindle are the key to the manufacturing process.