What is the difference between an absolute encoder and an incremental encoder And is it true that only absolute encoders can be used for returning to the origin

What is the difference between an absolute encoder and an incremental encoder? And can you only use an absolute encoder for returning to the origin? There are many forms of position encoders, such as the two mentioned in the title, as well as grating and magnetic grating encoders, Serial encoder and parallel encoder, etc. Encoders are mainly used for angular displacement measurement devices, such as angular displacement detection of motor rotor shafts.

What is an incremental encoder and what is an absolute encoder?

Take the angular displacement detection of the motor rotor shaft, the position encoding method has two types of output, one is the incremental counting output type, and the other is the absolute value output type. For the incremental output type, it is necessary to calculate the number of output signals to determine the actual angle of the motor rotor shaft, so it is called an incremental encoder. The detection signal can directly reflect the actual angle of the motor rotor, so it is called an absolute encoder.

Incremental encoder; it has three phases A, B, and Z, and the function of A and B phase is to determine the relative angular displacement and steering discrimination within the range of 360 degrees. The role of the Z phase is to determine the number of revolutions of the motor rotor shaft. Among them, phase A and phase B are counting pulses, phase Z is zero pulse.

Absolute encoder; its signal output can directly reflect the absolute angle in the range of 360 degrees, and its absolute position is identified by the amplitude of the output signal or the physical code scale of the grating. Although there are two ways of absolute position, if it is identified by the amplitude of the output signal, it is called a resolver. If it is identified by the physical code scale of the grating of the output signal, it is called an absolute encoder. The absolute encoder has many parallel physical encoder gratings and corresponding photoelectric converters. The 360-degree circumferential position is represented by binary or gray coded data divided equally.

The difference between absolute encoder and incremental encoder

The absolute value encoder can directly detect the absolute position when detecting the rotation angle, and does not need a backup battery to keep the data, and do not perform the reference point return operation, but the position data of the encoder cannot be adjusted or changed by the controller. Incremental encoders generally have no internal memory, so they do not have the function of keeping data after power off. They need to perform a reference point return operation in order to determine the counting reference and reset the actual position.

For example, is it possible to use absolute encoders only for returning to the origin in the title?

According to the above description of absolute encoder and incremental encoder, the title of "return to origin" is also "return to reference point". It can be seen from the above statement that if an absolute encoder is used, the “reference point return” operation is unnecessary, and if an incremental encoder is used, the “reference point return” operation is required. Therefore, it is not that the absolute value encoder should be used for returning to the origin. Whether or not to return to the origin depends on the type of encoder used.

What is the difference between an absolute encoder and an incremental encoder? Is it true that only absolute encoders can be used to return to the origin?