Position control in large mechanical joints has always been a balancing act between cost, robustness, and the level of detail engineers need to keep motion predictable. Optical encoders offer high resolution, but they introduce tight mechanical tolerances, bulky housings, and sensitivity to dust that does not always suit robots or off highway equipment. Melexis aims to give engineers a cleaner alternative with the MLX90520, an inductive encoder IC designed to deliver high resolution measurement without the fragility that comes with optical assemblies.
Why Inductive Sensing Suits Large Motion Systems
Robots and machinery with wide diameter joints place unusual demands on position sensors. The sensing structure has to span a large opening while still reacting to small angular changes. Optical disks can meet this requirement, but they add alignment complexity and tend to dislike contaminants that collect in enclosed mechanical spaces. Inductive sensing takes a different path. It measures position through the interaction between the IC and a printed target, which allows more freedom in mechanical design and removes several of the vulnerabilities associated with optics. In real systems this often means fewer service interruptions and more stable readings once the system accumulates dust or wear debris.
High Resolution Measurement Without Optical Constraints
The MLX90520 reaches 22 bit resolution for both rotary and linear motion, which is more than enough detail for industrial arms, large actuators, or long travel slides. The measurement path is essentially latency free, so control loops do not have to be tuned around sensing delays. One detail worth noting is the compact sensing module that can be built around the IC. A complete assembly can remain under three millimeters thick, even for wide through shaft joints. That profile is difficult to achieve with optical encoders or magnetic designs that typically require taller stacks or larger magnets to span the opening. Engineers working with 20 to 200 millimeter joints often appreciate this reduction because it simplifies the joint geometry.
Signal Integrity Through Integrated Digital Processing
Accuracy in inductive systems depends heavily on how the received signals are interpreted. The MLX90520 handles this internally through digital processing that corrects for variation in the target geometry. This improves stability across a wide range of operating conditions, including vibration and thermal drift. It also supports SPI and SSI interfaces, making it compatible with established industrial control architectures. The device meets system level SIL 3 requirements when used in suitable designs, which is a practical advantage for equipment that needs predictable behavior in safety related functions.
Lower Cost and Easier Integration for Robotics and Machinery
A recurring concern with high resolution encoders is the installation effort. Optical assemblies need precise alignment and careful protection from dust. Inductive modules built around the MLX90520 rely on a simpler target structure and only require a few parameters to be configured during setup. This tends to shorten development cycles, especially in projects where many joints share a similar design pattern. There is also a cost benefit because the inductive interface avoids the complex mechanics that often drive up the price of optical alternatives. In practice this lets teams scale designs across product families without carrying forward bulky or expensive encoder housings.
A Sensor Built Around Real Mechanical Environments
The strong interest Melexis is seeing is not surprising. Many designers have been looking for a position sensor that offers high resolution without forcing strict optical style constraints onto their mechanical architecture. By combining inductive sensing, thin packaging, and on board processing, the MLX90520 positions itself as a practical option for robots, construction equipment, agricultural machinery, and any system that needs accurate movement in less than ideal environmental conditions.
Learn more and read the original announcement at www.melexis.com
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