POSITAL provides support for SSI communications interfaces across its extensive family of IXARC absolute rotary encoders. This includes POSITAL’s innovative kit (modular) encoders and its versatile industrial encoders. Both types are now available in POSTIAL’s new miniature (20 mm diameter) form factor – the smallest multiturn absolute encoders on the market! For POSITAL’s larger encoders, SSI interfaces are available for a wide range of mechanical configurations, including 36 mm diameter compact designs, rugged 58 mm variants and 78 mm diameter “Explosion proof” (ATEX certified) models. In the larger sizes, both magnetic and optical measurement technologies are available.
Built-In or Stand-Alone
Kit encoders are “minimalist” motion sensors, designed to be built into a motor or other device, measuring rotary position directly from the host machine’s shaft. Without separate housings, shafts and shaft bearings, these sensors offer lower costs and more compact designs. By contrast, industrial encoders have their own shaft, supporting bearings and shaft seals. They can be installed virtually anywhere on a machine where it is important to monitor and control rotary motion.)
Why SSI?
SSI (for Synchronous Serial Interface) is a widely used communications protocol for many types of sensors. It is simple to implement and ideal for smaller systems where the extra capabilities of industrial Ethernet or fieldbus solutions are not needed. SSI is a serial communications system that connects sensors directly to digital PLC’s or microcontrollers through point-to-point wiring systems based on RS-422 communications standards. This offers high transmission rates and can support connections over distances of up to 1200 meters. SSI is supported by most major PLC manufacturers.
Advanced TMR Sensing and Battery-Free Multiturn Technology
Most POSITAL IXARC magnetic encoders feature advanced TMR (tunneling magnetic resistance) sensors for angular position measurement. TMR sensors are more stable, less temperature sensitive, and more responsive to small changes in the magnetic field than the Hall effect sensors used earlier. Moreover, they are significantly more energy-efficient than their predecessors. For multiturn versions, the rotation counting system receives power from an energy-harvesting Wiegand sensor, ensuring that every shaft rotation is accurately recorded in non-volatile memory – even if rotations occur when system power is not available. No backup batteries required!
Two Interfaces, One Encoder
POSITAL also offers IXARC encoders with a unique ‘hybrid’ communications interface that supports both absolute (SSI) and incremental measurements. While absolute measurements are ideal for many machinery positioning tasks, the excellent dynamic response of incremental encoders makes them a good choice for monitoring rotational speed and direction. Combining both measurement capabilities in a single device provides control system designers with extra flexibility, especially when a future upgrade from incremental rotation monitoring to absolute position measurement is planned.
Easy Parameter Setting with UBIFAST
POSITAL encoders with SSI interface are programmable: many operating parameters can be configured through simple software updates using POSITAL’s convenient UBIFAST programming tool.
