Discussion on Various Classifications and Differences of Encoders

Discussion on Various Classifications and Differences of Encoders

It is understood that encoders are generally divided into two types: incremental and absolute. The biggest difference is that in the case of incremental encoders, their position is determined by the number of pulses calculated from zero, while the position of absolute encoders is determined by the reading of the output code. In a circle, the output code reading for each position is absolute; Therefore, when the power is turned off, the absolute encoder will not separate from the actual position. If the power is turned on again, the position reading remains currently valid; Unlike incremental encoders, the zero mark must be found.
Encoder manufacturers have a complete set of products that are generally specialized, such as elevator specific encoders, machine tool specific encoders, servo motor specific encoders, etc. The encoders are intelligent and have various parallel interfaces to communicate with other devices.
The rotary incremental encoder outputs pulses during rotation and knows its position through a counting device. When the encoder is stationary or powered off, use the internal memory of the counting device to remember the position. In this way, when the power is cut off, the encoder cannot move at all. When the power supply is working, the encoder will not lose pulses due to interference during the output pulse process. Otherwise, the zero point memorized by the counting device will shift, and the shift amount will not be known until an incorrect production result occurs. The solution is to add reference points. Whenever the encoder passes through the reference point, the reference position is corrected to the memory position of the counting device. The accuracy of the position cannot be guaranteed before the reference point. Therefore, in industrial control, every operation has a way to find the reference point and start the machine to find the zero point. This type of encoder is determined by the mechanical position of the encoder disk and is not affected by power failure and interference.