Should I choose an incremental encoder or an absolute encoder2021

Rotary encoders include incremental encoders and absolute encoders. It is very confusing to choose which encoder to use in the equipment. We need to clarify our ideas. Before choosing which rotary encoder to use, you need to understand the following content:

1. How complex is your application?

2. What parameters (speed, position, direction) you need to control?

3. If there is a power failure, can you afford the cost of returning to the original position?

4. What performance level (number of pulses per turn) is required for your application?

5. How does the encoder communicate with other electronic devices in the system? Does your system need to communicate through one of a variety of communication protocols?

6. Is your application a cost-sensitive application?

Incremental encoders are generally only suitable for simple applications, no matter whether the control equipment is a counter, PLC or inverter, you can directly connect the encoder and the controller.

The difference between absolute encoder and incremental encoder

The biggest disadvantage of an incremental encoder is that it will not track any incremental changes output by the encoder when the system is powered off (such as a temporary power failure).

Therefore, in order to provide accurate position data, the incremental encoder must return to the initial position when it is started. For applications where the conveyor will be shut down every night and then restarted every morning, the return of the incremental encoder to the initial position will not affect the application. However, in applications such as automotive assembly robotic arms, if the power is cut off during the welding of the seat bracket, the return of the incremental encoder to the initial position will seriously damage the product and the robotic arm. Absolute encoders are ideal for high-reliability applications.

Unlike incremental encoders, absolute encoders do not output pulses, but output digital signals to indicate the encoder position, and use the encoder position as a static reference point in the absolute coordinate system. Therefore, the absolute encoder can still save its absolute position record when the power is off. After restarting, the system can resume movement immediately without returning to the original position.

The absolute value type rotary encoder has a code disc and a fixed grating connected to the shaft, allowing the system to generate a unique binary identifier for each travel point. As the code wheel rotates to the fixed grating, the system periodically reads the identifier and outputs it as a multi-digit digital signal. The relevant controller or frequency converter can poll the encoder to capture the position data, and can directly use the data or process it as speed information.

After understanding the above information, I believe you should have a bottom line about which encoder you want to choose.