CDHD High Performance Servo Drives
Wednesday, 11 November 2015

Safe Torque Off in CDHD Servo Drives Approved for SIL 3/PL e Cat.4

Functional safety in Servotronix CDHD servo drives is achieved through the safe torque off (STO) function, which by disabling the drive’s output ensures that it cannot generate torque in the motor thereby preventing uncontrolled starting or stopping of machinery.



As part of the company’s efforts to continually improve our product offering while meeting market demands for functional safety, Servotronix has obtained SIL 3/PL e Cat.4 certification for the STO (Safe Torque Off) safety function, in accordance with IEC 61800-5-2, for selected products of the CDHD 120/240 VAC servo drive family. The STO safety function complies with the requirements laid down in DIN EN 61508 for use up to and including SIL 3 (Safety Integrity Level),and the the requirements of DIN EN ISO 13849 for use at Category 4 and Performance Level  e (PL e. SIL 3 and PL e are the functional safety compliance ratings most commonly requested by machine builders. This helps machine builders to incorporate high safety integrity into their machine designs when they integrate Sevotronix’ CDHD drives.