The sensor specialist MTS has developed a linear motion sensing technology that combines an incremental interface and an absolute output – such as Synchronous Serial Interface (SSI) – in the same housing. It says that this configuration will allow more precise position and speed control in linear applications by providing feedback to both the drive and the motion controller.

“A dual-function sensor is something our customers have been asking for in a magnetostrictive linear positioning product for some time,” explains Matt Hankinson, technical marketing manager for MTS Sensors. “Currently, designers using an incremental encoder who want to add absolute position feedback must add an additional linear encoder or use a proprietary interface. The new dual sensor will provide both an incremental quadrature signal to the drive, and an absolute linear position feedback for motion control with a single sensor.”

One potential application is for linear motors that would normally use an incremental linear encoder for drive commutation (switching the current in phases to drive the motor position and speed). The two-channel sensor could produce an incremental signal for driving the motor position, while providing an absolute linear position feedback channel to the motion controller.

The new device works at two levels. The incremental interface measures changes in position, while the SSI output communicates the absolute position of the sensor, avoiding the need for calibration. When combined with non-contact sensor technologies, MTS says that this can cut installation and maintenance costs, while boosting productivity. Also, the absolute technology does not “lose track” of its position, regardless of the traverse speed.

MTS expects to launch the first product to use the new technology in the first half of 2012, as part of its Temposonics range.