In a previous blog, we discussed the function and capabilities of a linear encoder, but what applications does a rotary encoder possess? A rotary encoder is known for its tracking ability, which provides continuous information on current shaft position. Rotary encoders are also used to monitor speed, distance, and the direction of the shaft movement. To help you understand the ability and function of a rotary encoder, Leading Edge Industrial has compiled helpful tips for encoder operation.
What is the Function of a Rotary Encoder?
A rotary encoder is an excellent tool for determining exact shaft position, as well as for monitoring speed control and positional accuracy. A rotary encoder also offers high resolution. By providing information about speed and position accuracy, this encoder allows users to program more concise machinery movements.
How Does a Rotary Encoder Operate?
Just as the linear encoder discussed in a previous blog had multiple encoder distinctions, so does a rotary encoder. A rotary encoder can be classified as ‘incremental’ or ‘absolute’ and read through magnetic, optical, laser, and quadrature signals.
The basic configuration of a rotary encoder begins with a simple disc that contains equally spaced contact zones and two pins labeled “A,” and “B.” On the same disc is a common pin labeled “C.” When the shaft rotation begins, the “A” and “B” pins will come into contact with the common “C” pin, and their wave output signals will be generated. The “A” and “B” signals are situated 90º degrees out of phase with each other—creating opposite values. This setup makes for easy readability and documentation of shaft position for a rotary encoder.
How Does a Rotary Absolute Encoder Operate?
Not all rotary encoders operate in the same fashion. To provide an example of how encoders can differ in design, I will detail the makeup of a rotary absolute encoder. This encoder consists of a disc, light source, detector, and microcontroller. It operates by using a disk that contains concentric circles of interchanging segments (the differing segments are opaque and transparent). For each circle on the disc, there is a unique/different pattern of slots which allows light through to the detector. The light detector generates a high/low pulse by sensing the signal of light allowed through the etched markings on the disc. This read information is then transferred to the microcontroller, which reads the new information and relays the output (in the form of position status). Though the design of rotary encoders can differ, the basic function of these encoders will not.
For reference, a rotary encoder resolution is measured as pulses per revolution (PPR).
When Should I Use a Rotary Encoder?
Deciding whether or not to use a rotary encoder can be a tough decision, but the benefits of these encoders are highly valuable. The following industries use encoders to monitor position and improve accuracy within their machines:
The Automotive Industry:
The automotive industry utilizes rotary encoders to control speed components within vehicles.
Industrial Machinery:
Encoders are used in combination with CNC machines, as well as other machinery like packaging machines, drilling devices, and labeling appliances.
The Medical Industry:
In the health field, accuracy and precision are required in medical machinery. Rotary encoders are used to help control speed and monitor position in machines like scanners, dispensing pumps, and similar technology.
Military Equipment:
Military machinery often uses rotary encoders to help position antennas on different devices.
Used with Spindles:
Spindles are commonly used in machinery to help hold and power cutting tools that are found on milling machinery and lathes. A rotary encoder can be used with a spindle to increase accuracy and provide position feedback to users. The primary benefit of a rotary encoder on a spindle is for threading operations.
Listed above are just a few examples of the wide array of industries in which rotary encoders can be used. Prized for increasing positional accuracy, monitoring speed control, providing high resolution, and possessing the ability to be used with digital technology, rotary encoders will continue to increase in popularity—sure to become a necessity in this modern age where accuracy is critical.
For further questions concerning rotary encoders, contact Leading Edge Industrial.
Sources:
https://www.anaheimautomation.com/manuals/forms/encoder-guide.php
https://www.flickr.com/photos/sparkfun/15659597894