ABB MicroFlex e150 User Manual

Appendix: Safe Torque Off (STO) 173
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Appendix: Safe Torque Off
(STO)
What this chapter contains
The appendix describes the basics of the Safe torque off function (STO) for the
MicroFlex e150. In addition, application features and technical data for the safety
system calculation are presented.
Basics
The STO function disables the control voltage of the power semiconductors of the
drive output stage, which prevents the inverter generating the voltage required to
rotate the motor (see diagram below). By using this function, short-time operations
(like cleaning) and/or maintenance work on non-electrical parts of the machinery can
be performed without switching off the power supply to the drive.
The drive supports the Safe Torque Off (STO) function according to standards
IEC 61800-5-2, EN 61508:2010, EN ISO 13849-1 and IEC 62061:2005.
See Safety Manual: Safe Torque Off (STO) function for MicroFlex e150 drives
(LT0313...) before using the STO function.

ABB MicroFlex e150 Specifications

General

Brand	ABB
Model	MicroFlex e150
Category	Control Unit
Language	English