- July 06, 2020
- POSITAL - Fraba Inc.
June 7, 2020 – Sensor manufacturer POSITAL has introduced an alternative for safety-critical motion control systems. Supplementing its existing range of formally certified SIL safety encoders, the ‘diverse-redundant absolute encoders’, based on non-certified standard components, are a choice for many installations where functional safety is required. When combined with functional safety PLCs, these devices are suitable for applications that are required to conform to Performance Level/ PL d, Cat. 3, according to ISO 13849.
‘Redundancy’ means that these devices contain two independent sensor systems. Measurements from these two systems are processed by a functional safety PLC. If both measured values are the same (within defined tolerances), safe operation is assumed. If there are deviations, the controlling PLC triggers an alarm - with the option of transitioning the system to a defined safe condition. To be on the safe side, POSITAL makes use of a combination of magnetic and optical sensor technology - the key words are diverse redundancy. Applications for the safety-ready encoders range from heavy construction equipment and mobile machines, through crane technology and elevators, to complex stage technology for theatrical or film productions.
Instead of installing the redundant systems in separate housings, POSITAL has chosen an all-in-one solution. The magnetic and optical sensor elements are integrated in a housing that is 58 mm in diameter.. Resolution is 16 bits per revolution. Like other products in the modular POSITAL portfolio, the encoders are available with a variety of mechanical options. The spectrum ranges from housings, designed for protection levels up to IP67, through different connector types, to many flange and shaft variants (hollow or solid shaft). Communications is through the well-established CANopen interface. The safety-ready encoders are suitable for harsh environments and a wide temperature range. Both sensor elements, optical and magnetic, are absolute encoders that measure the position value in single and in multi-turn mode – absolutely battery- and maintenance-free.
The new are suitable for applications requiring functional safety up to Performance Level/PL d, Cat. 3 of ISO 13849.. Individual parameters - like the exact specifications for activating the 'Safe State' function - can be programmed into the PLC by the system integrator.