The positional information of InAxis™ absolute encoders is integrated directly into a piston rod or a shaft guide of the actuator itself.
The shaft consists of a magnetic hardened steel core with tiny structures on its surface. The shaft core is covered by a thin, non magnetic hard chrome layer. The readhead comprises a custom made ASIC and a permanent magnet acting as a passive actuator, inducing a magnetic field on the surface of the shaft.
As the readhead moves along the shaft, the tiny structures on the surface of the shaft cause variations in the magnetic field. These variations are detected by several Hall sensors in series and are evaluated by a microprocessor using a patent pending solution to provide absolute position information with resolutions up to 0.5 μm.
The shaft is used both as a load-bearing functional part of the actuator as well as en encoder scale. The InAxis™ encoder technology means a direct on-the-spot position measurement and has several advantages to parallel encoder systems, like reduction of system's components, better accuracy, higher reliability and no hysteresis.