Comparing Absolute And Incremental Encoders

Digital readout units or DRO systems are a key part of CNC equipment. Functioning mainly with the help of encoders, the DRO offers accurate position readings of the cutting tool and workpiece across multiple axes. In the previous blog, 3 main types of digital encoders were addressed. However, even within this classification, encoders can be further divided into absolute and incremental encoders. This blog aims to clarify the differences between these two.

What Are Absolute And Incremental Encoders?

Absolute Encoders

In the case of an absolute encoder, there is a fixed, constant, starting point. Hence, the zero point or starting point is not related to any other metric or measurement. Here is an example of how it works in a rotary encoder. In this setup, a slotted disc is mounted on a shaft which is in conjunction with a stationary measuring device. Once the shaft begins its rotation, the movement pattern is registered as a unique code. Therefore, each type of motion of the shaft has its own unique code pattern which is used to determine its exact position at all times.

Incremental Encoders

For incremental encoders, the measurement of linear or rotary motion is connected to a relative starting point. Equidistant markings are placed on the scale for linear encoders and on the disc for rotary encoders. Depending on the marking, the encoder generates a pulse or signal, which is then translated to a readout.

Therefore, using the example of rotary encoders like in the case above, for incremental encoders, the device will go to the starting point or zero each time when it is turned on. Therefore, the reference point should be set carefully before beginning a new task.

Walker Machinery Inc. is one of the leading suppliers of all CNC control equipment in Canada. From DRO systems to digital encoders such as linear, angle and rotary encoders, we guarantee top-notch quality in all our products. The company also combines impeccable quality with exceptional customer service. For more product details or queries, reach out to us today at 905-876-0890.