POSITAL expands SSI options for IXARC encoders

POSITAL now supports SSI communication interfaces across a broad range of IXARC absolute rotary encoders. This includes both kit (modular) encoders and industrial encoders. Both are also available in POSITAL’s new 20 mm miniature form factor.

For larger encoders, SSI interfaces are offered in several mechanical configurations, including 36 mm compact models, 58 mm rugged versions, and 78 mm explosion-proof models with ATEX certification. In these larger sizes, customers can choose between magnetic and optical measurement technologies.

SSI, or Synchronous Serial Interface, is a commonly used communication interface for many types of sensors. It is straightforward to implement and well suited to smaller systems that do not require the added functionality of industrial Ethernet or fieldbus networks. SSI is a serial communication method that connects sensors directly to digital PLCs or microcontrollers through point-to-point wiring based on the RS-422 standard. It supports high transmission rates and connection distances of up to 1,200 meters. SSI is also supported by most major PLC manufacturers.

Most POSITAL IXARC magnetic encoders use TMR (tunneling magnetoresistance) sensors for angular position measurement. Compared with earlier Hall-effect sensors, TMR sensors offer greater stability, lower temperature sensitivity, better response to small changes in magnetic fields, and improved energy efficiency. In multiturn versions, the rotation counting system is powered by a Wiegand energy-harvesting sensor, which records each shaft rotation in non-volatile memory, including rotations that occur when system power is unavailable. No backup battery is required.

POSITAL also offers IXARC encoders with a hybrid communication interface that supports both absolute (SSI) and incremental measurements. Absolute measurement is well suited to many positioning tasks, while incremental encoders are often used for monitoring rotational speed and direction because of their dynamic response. Combining both functions in one device gives control system designers more flexibility, particularly when a future transition from incremental monitoring to absolute position measurement is being considered.

POSITAL encoders with SSI interfaces are programmable, and many operating parameters can be configured through software updates using POSITAL’s UBIFAST programming tool.