1、 Absolute value encoder

There are many optical channel lines on the optical code disk of the absolute value encoder, each line is arranged in sequence of 2, 4, 8, and 16 lines. In this way, at each position of the encoder, by reading the on and off of each line, a unique binary code (Gray code) from the zero power of 2 to the n-1 power of 2 is obtained, which is called an n-bit absolute value encoder. This type of encoder is memorized by a photoelectric encoder.

The absolute value encoder is determined by the mechanical position for encoding, without the need for memory, reference points, and continuous counting. When the position needs to be known, its position can be read. In this way, the anti-interference characteristics of the encoder and the reliability of the data are greatly improved.

From a single turn absolute value encoder to a multi turn absolute value encoder, the absolute value rotates the single turn absolute value encoder to measure the various lines of the photoelectric code disk during rotation, in order to obtain a unique encoding. When the rotation exceeds 360 degrees, the encoding returns to the origin, which does not comply with the principle of absolute encoding uniqueness. This encoding can only be used for measurements within a rotation range of 360 degrees, and is called a single turn absolute value encoder.

This is a detector that can output the angle data within one revolution of the motor to external targets. Absolute value encoders can generally output 360 ° with 8 to 12 bits

The incremental encoder has a drawback: it loses the axis position when a power failure occurs. However, for absolute value encoders, even in the event of a power failure, the axis position is not lost. It can output various codes, such as binary code and BCD code.

Absolute value encoders are more expensive, precise, and larger than incremental encoders. Textile machinery, irrigation machinery, papermaking and printing, water gates, robots and robotic arms, port lifting machinery, steel and metallurgical equipment, heavy machinery equipment, precision measurement equipment, machine tools, food machinery, elevators and other special equipment.

2、 Working principle of absolute value encoder

There are many optical channel lines on the absolute encoder optical code disk, each line is arranged in 2, 4, 8, and 16 lines in sequence. At each position of the encoder, by reading the on and off of each line, a unique binary code (Gray code) from the zero power of 2 to the n-1 power of 2 is obtained, which is called an n-bit absolute value encoder. This type of encoder is determined by the mechanical position of the photoelectric encoder and is not affected by power outages or interference.

The absolute value encoder is determined by the mechanical position for encoding, without the need for memory, reference points, and continuous counting. When the position needs to be known, its position can be read. In this way, the anti-interference characteristics of the encoder and the reliability of the data are greatly improved.

3、 Difference between single turn/multi turn absolute value encoders

Single turn absolute value encoder to multi turn absolute value encoder.

Absolute value rotation single turn absolute value encoder measures each line of the photoelectric code disk during rotation to obtain a unique encoding. When the rotation exceeds 360 degrees, the encoding returns to the origin, which does not comply with the principle of absolute encoding uniqueness. This encoding can only be used for measurements within a rotation range of 360 degrees, and is called a single turn absolute value encoder.

When measuring a rotation beyond 360 degrees, a multi turn absolute value encoder is used. The encoder production uses the mechanical principle of clock gears. When the center code disk rotates, another set of code disks (or multiple sets of gears, multiple sets of code disks) are driven by gears. On the basis of single turn coding, the number of turns is increased to expand the measurement range of the encoder. This type of absolute value encoder is called a multi turn absolute value encoder. It is also determined by the mechanical position for coding, and each position code is unique and not repeated, without the need for memory.

Another advantage of multi turn encoders is that due to their large measurement range, they are often used with more margin, so there is no need to struggle to find the zero point during installation. A certain middle position can be used as the starting point, greatly simplifying the difficulty of installation and debugging.

Shenzhen Zhongling Technology is a national high-tech enterprise that focuses on research and sales. As a high-tech company that integrates the research and development, production, and sales of wheel hub servo motors and drives, Shenzhen Zhongling Technology (www.zlingkj. com) has a strong research and development team. I believe that there will be more breakthroughs in the future.