The difference between magnetic encoder and photoelectric encoder

Release time:

2023-11-08 02:00

The main components of a magnetic encoder include a magnetoresistive sensor, a magnetic drum, and a signal processing circuit. The magnetic drum records small magnetic poles at equal intervals, which, after magnetization, form a regularly dispersed spatial leakage magnetic field as they rotate. The magnetic sensor probe converts the changing magnetic field signal into a change in resistance value based on the magnetoresistive effect and applies a voltage. Under action, the changing resistance value is converted into a voltage change.

After the analog voltage signal is processed by the signal processing circuit in the later stage, it is converted into a digital signal that can be recognized by the computer, thereby realizing the encoding function of the magnetic rotary encoder. Therefore, the magnetic encoder adopts a magnetoelectric design scheme.
The photoelectric encoder consists of a light source, a code disk, and a photoelectric receiver, among which the code disk is an important part of the encoder. The photoelectric encoder is mainly used for measuring displacement or angle. The material of the encoder disk for traditional photoelectric encoders usually includes glass, metal, and plastic. The glass encoder has deposited very fine lines on the glass, which can meet the general standards and requirements for heat stability and accuracy, but is very prone to cracking.

Characteristics and advantages of magnetic encoders:

Strong anti-interference ability: Magnetic encoders are not affected by electromagnetic interference in the environment and are suitable for complex environments such as high magnetic fields and strong vibrations.
High precision: Magnetic encoders can achieve high resolution and accuracy, suitable for applications with high measurement accuracy requirements.
Easy installation: The structure of the magnetic encoder is relatively simple, easy to install, and does not require complex optical systems.
Wide temperature range: Magnetic encoders typically have a wide operating temperature range, suitable for working environments with significant temperature changes.
Corrosion and pollution resistance: The magnetic drum and pole structure of the magnetic encoder can operate stably for a long time in harsh working environments, and has strong corrosion and pollution resistance performance.

Characteristics and advantages of photoelectric encoders:

Smaller size: The encoder disk of the photoelectric encoder can be made of smaller sized materials, suitable for applications with limited space.
Low cost: Due to the relatively simple structure of the photoelectric encoder, the manufacturing cost is relatively low.
High reliability: Traditional photoelectric encoders have been validated for a long time and have high reliability.
Not affected by magnetic field: The photoelectric encoder is not affected by external magnetic fields and is suitable for working environments with high magnetic field interference.
High speed applications: Due to the fact that photoelectric encoders do not require complex arithmetic processing, they are suitable for high-speed motion control.
Magnetic encoders and optoelectronic encoders are common rotation or displacement sensors, and they have some differences in working principles, characteristics, and advantages. Magnetic encoders have advantages such as strong anti-interference ability, high accuracy, wide temperature range, corrosion and pollution resistance, and are suitable for applications with high requirements for accuracy and stability. Optoelectronic encoders have advantages such as small size, low cost, and high reliability, making them suitable for applications with high cost and space requirements.

When selecting an encoder, it is necessary to comprehensively consider its characteristics and advantages based on the specific application requirements to ensure the selection of the most suitable encoder to meet practical application requirements. Both magnetic and optoelectronic encoders play an indispensable role in modern automation control systems, providing strong support for the development of the industrial field