What is an absolute encoder and how does it work?
An absolute encoder is an advanced device used in industrial automation that is used to accurately determine the position of an object. Unlike an incremental encoder, which provides relative motion information, an absolute encoder is able to provide a unique code for each position, allowing the location to be tracked even after a power loss. As a result, there is no need to perform a reference procedure after restarting the system, which is a great advantage in many industrial applications.
The principle of an absolute encoder is based on generating a code that uniquely corresponds to a specific position of an axis or shaft. Depending on the type of encoder, this can be accomplished using various technologies, such as optical, magnetic, inductive or capacitive. Each of these technologies has its own specific applications and is chosen depending on requirements for accuracy, environmental resistance or cost.
Types of encoders in industrial automation
In the world of industrial automation, encoders play a key role in monitoring and controlling the movement of machines. There are many types of encoders that differ in their mode of operation, construction and applications. The two main types are rotary encoders and linear encoders, which are essential in many industrial applications.
Rotary and linear encoders
Rotary encoders are used to measure the angle of rotation of a shaft or axis. They are invaluable in applications such as robotics, where precision of movement is crucial. Linear encoders, on the other hand, are used to measure precise linear motion, for example in CNC machines or conveyor systems. Each of these types of encoders has its own specific applications in industry, depending on the accuracy requirements and the type of motion to be monitored.
Optical and magnetic encoders
Among rotary and linear encoders, we can also distinguish optical and magnetic encoders. Optical encoders operate on the principle of interrupting a beam of light through a specially designed disk or tape, which allows for highly accurate measurements. They are ideal for applications where high precision is required, but can be susceptible to dirt, which can affect their performance. On the other hand, magnetic encoders use magnetic fields to generate signals. They are more resistant to contamination and vibration, making them suitable for harsher industrial environments. The choice between optical and magnetic encoders often depends on the specific application and the conditions under which the device will operate.
How to connect and mount an encoder?
Connecting and installing an encoder may seem complicated, but with the right tips it will become much simpler. Below you will find practical tips to help you properly install an encoder in your industrial automation system.
The first step is to choose the right encoder housing. Enclosure types vary depending on the operating environment and application-specific requirements. For example, in environments exposed to a lot of dust and moisture, enclosures with a high IP rating will work best. On the other hand, standard enclosures can be used in less demanding conditions.
The next step is the physical assembly of the encoder. Here it is crucial to ensure that the encoder is properly centered and stably mounted to avoid errors in position reading. For rotary encoders, it is important that the encoder axis is perfectly parallel to the shaft’s axis of rotation. For linear encoders, care should be taken to make the motion path as linear as possible.
Connecting the encoder to the control system is the next important step. Here you need to pay attention to the type of encoder output signal and match it to the controller inputs. Many modern encoders offer a variety of connection options, including analog and digital, allowing for flexibility in matching different systems.
How to choose an encoder for your application?
Choosing the right encoder for a specific industrial application may seem complicated, but understanding a few key factors will make it easier to make the right decision. In this guide, we will focus on how to select an encoder for an application, paying special attention to the quality of the encoder’s output signal and other important aspects.
The first step in selecting an encoder is to determine the type of motion to be monitored – whether it is rotary or linear. This will determine whether you need a rotary or linear encoder. Next, it is important to understand the environment in which the encoder will operate. Factors such as temperature, humidity and the presence of contaminants can affect the choice of encoder type – optical or magnetic.
Another key element is the quality of the encoder’s output signal. Encoder output signals can be analog or digital, and their choice should be matched to the control system with which the encoder will work. Digital output signals, such as Ethernet or CAN, are often preferred in modern applications due to their greater immunity to noise and greater transmission range.
It is also worth noting the encoder’s resolution, which is the number of pulses per revolution for rotary encoders, or per unit length for linear encoders. Higher resolution means greater precision, but can also come at a higher cost.
Applications of encoders in industry
Encoders, which are key components in industrial automation, are used in many industries. Their ability to precisely monitor and control position and motion makes them indispensable in many advanced manufacturing systems and machines. In this section, we take a look at how encoders are used in various industries, highlighting their importance and versatility.
In the automotive industry, encoders are used to control industrial robots involved in vehicle assembly. The precision offered by encoders allows for the accurate placement and assembly of complex components, which is key to maintaining high production quality. Similarly, in the aerospace industry, where absolute accuracy is required, encoders are used to monitor the position of aircraft wings and other critical components.
In the food production sector, encoder applications include packaging and sorting machines. Encoders help with precise product positioning, which is essential for efficient and hygienic food packaging. In the textile industry, encoders are used to control weaving machines to ensure uniform material quality.
In each of these cases, encoders play a vital role in improving the efficiency, accuracy and reliability of production processes. Their ability to operate in harsh industrial environments, where dust, vibration and extreme temperatures are the norm, further underscores their value. With encoders, companies can automate processes, minimize errors and increase overall productivity.
In summary, encoders are not only key components in industrial automation, but also invaluable tools in a wide variety of industrial sectors. Their versatility and reliability make them a valuable component of modern manufacturing technologies, contributing to industrial development and innovation around the world.
Michał Gałdyn
Technical Director
AMG Industry Supply and Automation