Encoders

Encoders for small DC motors

In the era of Industry 4.0, manufacturers from all industries rely on fast and accurate forms of measurement. In addition to using external sensors, encoders can provide accurate feedback integrated directly into a drive system. They monitor motor movement and transmit position, in real time, via digital signals.

A typical motor encoder will provide an electric signal used to monitor the speed and/or position of the mechanism. This feedback allows the control system to establish whether the object being monitored is moved or positioned correctly and allows adjustments to be made accordingly.

There are several types of encoder used on motors, and offered by EMS.

Absolute encoders

In combination with small DC motors, such as the FAULHABER BX4 brushless motors, absolute encoders are ideal for commutation, rotational speed control and position control. Being absolute means that each shaft position within a revolution is assigned a unique angular value. The encoder determines absolute positions, not relevant positions like an incremental encoder achieves.

FAULHABER offers both single-turn and multi-turn encoders. More information about FAULHABER absolute encoders, which are stocked exclusively for the UK and Ireland by EMS, can be found here.

Incremental encoders

Incremental encoders transmit a specific number of uniformly distributed lines per revolution and are one of the most commonly used types of rotary encoder. Unlike absolute encoders, incremental encoders provide relative positions and, as such, incremental encoders will only determine a position relative to another reference position. 

All FAULHABER incremental encoders boast at least two channels. Both channels supply a square wave signal, phase shifted by 90° with respect to one another. The motors direction of rotation is determined by this shift of pulses. EMS recommends the FAULHBAER IER3-10000 (L) series for many incremental encoder applications, which features a very high resolution of up to 40,000 edges per revolution and exceptionally high position accuracy, repeatability and high signal quality.

More information on FAULHABER incremental encoders can be found here.

Optical encoders

An incremental or absolute encoder can come in the form of on optical encoder. This type of encoder uses light shone through a coded disk to track the movement of a shaft. The encoder provides feedback based on the interruption of that light.

Optical technology can achieve extremely high resolutions, and thus applications that demand a high level of accuracy may favour the technology. As mentioned previously, the FAULHABER IER3-10000 (L) is a great example of an optical incremental encoder, suitable for applications as diverse as industrial automation, CNC machining, medical and lab equipment and pulp and paper production, as well as many other instances that require high accuracy position monitoring.

Magnetic encoders

A magnetic encoder detects rotational position information as changes of a magnetic field created by a small magnet on the rear motor shaft, converts them into electrical signals and then outputs them. They are especially insensitive to dust, humidity and thermal and mechanical shock so are ideal for demanding applications and environments.  

Magnetic encoders are often used in robotics applications, but can be beneficial for many kinds of industrial automation application. From FAULHABER, EMS recommends the IE3-1024 (L) series that consists of a diametrically magnetised, two-pole sensor magnet fastened to the motor shaft. The series features a compact modular system with robust housing, standardised electronic encoder interface and multiple resolution options.

Line Drivers

Most encoders from FAULHABER can be optioned with a line driver, which gives a differential output signal for all channels. This eliminates the effect of electromagnetic interference on the encoder output and allows for signal transmission over a greatly increase line length further increasing the robustness of the complete drive system.

EMS stocks a vast range of encoder variations from FAULHABER, which can be combined with the complete portfolio of FAULHABER DC, brushless, and stepper motors. For more information on the types of encoder EMS can recommend for your application, contact the team.