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STO Implemented in Compact High Power Density Servo Drive


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STO Implemented in Compact High Power Density Servo Drive

TECHNOSOFT is pleased to inform all its partners that selected products of the iPOS servo drive family now benefit from the certification for the STO (Safe Torque Off) capability.

As part of the company’s effort to continually improve our product offering while meeting market demands for functional safety, TECHNOSOFT can now propose two versions of the iPOS4808 MY family that benefit from a high degree of performance from the STO implementation point of view : SIL3 and PLe in accordance with EN 61800-5-2 standard.

The Safe Torque Off function safely validates the pulses controlling the power stage of the drive. When activated, the drive is reliably torque-free. This state is monitored internally in the drive.

The STO function is implemented using simple solid state hardware for high reliability reasons. Since on the classic safety circuit the redundancy is done by 2 contactors connected in series with the motor, on integrated STO function the redundancy is done using 2 separate STO opto-isolated inputs. If both STO inputs are in “high” state, the motor is allowed to generate torque. If at least one of 2 STO inputs will not be in “high” state, the power stage will become inactive (no pulses controlling the power stage) and the motor will be free of torque.

The advantage of the integrated STO (SIL3, Cat3, PL-e) safety function compared with electromechanical safety technology based on contactors is the elimination of separate electromechanical components and the effort that would be required to wire and service them. The electrical arching is totally eliminated. The overall dimensions of integrated STO solution are highly reduced, while the cost reduction is also very important compared to classic electromechanical technology.

With certification granted by the recognized body TÜV SUD, the iPOS4808 MY drives with STO represent the ideal solution for most applications that require 48V and up to 8A continuous current with either CAN (iPOS4808 MY-CAN-STO) or EtherCAT (iPOS4808 MY-CAT-STO) and any type of brushed, brushless, linear or step motor.

This allows users to reduce the system’s cost, while increasing the safety level of their application.


48595 Wildrose Drive
Canton , MI 48187
United States

Map for Technosoft in Canton MI US

Technosoft is a leading motion control technology company specialized in the development, design and manufacture of …
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