Encoders

Operating Principle and Types of Encoders in Industrial Automation

In practice, encoders are divided into two main types – incremental and absolute. Their operation depends on how the signal is processed and how information about the shaft position is transmitted.

An incremental encoder generates electrical pulses during motion. Each pulse corresponds to a specific angular or linear displacement. By counting these pulses, the control system can register the direction, speed, and number of rotations. This is why it is perfectly suited for dynamic drive structures where fast reading and system response are required.
Absolute encoders, on the other hand, provide unambiguous information about every angular position. The absolute type assigns a unique code signal to each position, so it retains position information even after a power failure. This solution is essential in applications where operational continuity and positioning safety are crucial.

Modern automation systems can often be divided into incremental and absolute, depending on process requirements. Magnetic or optical encoders are also increasingly used, differing in the way motion is read – magnetic relies on changes in the magnetic field, while optical relies on the interruption of an LED beam by a code disc.

Incremental Encoder

The incremental encoder is the most commonly chosen type in industry. Its operating principle involves generating a series of pulses per revolution, which are then counted by the PLC controller for control. In this way, the system can determine the rotational speed, direction, and number of rotations performed.

Thanks to its simple design and high resolution, the incremental encoder provides accurate measurement and easy integration with machines. It is widely used in electric motors, CNC machines, conveyors, and packaging lines. Its advantages include compact design, durability, and resistance to vibrations and harsh environmental conditions.

Absolute Encoders

Absolute encoders are used where position retention after a power failure is crucial. Each axis position is assigned to a binary code, ensuring full control over positioning. An absolute encoder does not require zeroing after restarting the machine, which reduces downtime and increases the efficiency of production lines.

Absolute encoders are suitable for robotics, positioning systems, and motion monitoring systems where high precision and reliability are essential. Thanks to modern technologies such as SSI, HTL, and TTL, direct communication with the automation system and immediate position readout are possible.

Linear Encoders

In addition to rotary versions, linear encoders are gaining increasing popularity, measuring the displacement of elements along a specific axis. A linear encoder is used in machine tools, transport trolleys, measuring wheels, and CNC systems where precise determination of position and distance is necessary.
Thanks to high resolution and resistance to interference, a linear encoder provides high accuracy and repeatability of measurement, which is crucial for industrial automation and quality control.

Encoder Construction and Mounting

The construction of an encoder includes elements such as a shaft (or a hollow shaft in the case of hollow-shaft encoders), a code disc, an optical or magnetic sensor, an interface system, and a highly resistant housing.
Encoders often have mounting brackets for encoders, which facilitate installation in drives. Models with a 6 mm shaft or other standard shaft are also available, allowing the device to be adapted to various types of motors and applications.

Depending on the needs, the encoder can be connected to the system using interfaces such as SSI, VGA, HTL, or RS422, enabling direct transmission of the output signal.

Magnetic and Optical Encoders

In modern industrial applications, magnetic encoders and optical encoders dominate.
Magnetic encoders use changes in the magnetic field to generate electrical pulses, allowing them to operate in harsh conditions with high dust and humidity. Optical encoders, on the other hand, rely on precise reading from a disc with transparent and opaque sectors, enabling very high measurement resolution.

Both technologies are widely used in automation, where encoders provide information about speed, position, and direction of rotary or linear motion.

Application of Encoders in Industry

Rotary encoders are commonly used in many industries, in PLC control systems, motor drives, CNC machines, conveyors, assembly lines, and positioning systems. Thanks to their accuracy and reliability, encoders enable control of rotary or linear motion and full synchronization of processes.
Encoders are also used in monitoring systems, robotics, automation, and energy, where they provide a unique level of precision in angle and displacement measurement.

How to Choose an Encoder for Industrial Application

Selecting the right encoder depends on the application type, measurement parameters, interface type, and operating conditions. It is necessary to determine whether an incremental encoder or an absolute encoder is needed, what measurement resolution the system requires, and whether a magnetic, optical, or mechanical version is preferred.
The mounting method is also important – encoders are available with a mounting hole, drive shaft, or adapted for flexible couplings.

Encoder Offer and Service at PLE Service

Our offer includes incremental and absolute encoders, magnetic encoders, optical encoders, as well as encoder accessories – couplings, mounting brackets, and signal cables.
PLE Service provides sales, selection, encoder service, repair, and diagnostics. We offer support in integrating devices with PLC systems and assistance in selecting an encoder for every industrial application.

Every encoder in our offer is a precise transducer designed for demanding environments, guaranteeing reliability, measurement accuracy, and long lifespan even in harsh conditions.