POSIHALL is ASM Sensors' (Elmhurst, IL) new magnetic multiturn encoder technology. According to the company, the new encoder technology measures true-absolute and is the robust alternative to optical encoders. It measures absolute angular position of a shaft over multiple revolutions by using a gear-coupled multi-hall sensor system that uses a magnetic nonius (vernier) principle. In contrast to current magnetic encoder technologies, POSIHALL's true-absolute technology ensures reliable and correct positioning even after disturbances such as a power failure. POSIHALL sensors can be mounted directly onto the machine’s rotation axis. Available in protection class up to IP69, the sensor electronics are completely enclosed and protected by a rugged housing. The non-contact magnetic multi-hall technology is able to reliably detect measuring data even if the machine housing is filled with water or oil. The sensor body has an integral shielding against magnetic fields.