Function Description - Siemens SINAMICS G115D Operating Instructions Manual

Advanced commissioning
7.15 Safe Torque Off (STO) safety function
7.15.1

Function description

A converter with active STO function prevents energy supply to the motor. The motor can no
longer generate torque at the motor shaft.
Consequently, the STO function prevents the starting of an electrically-driven machine
component.
Principle of operation of STO
1. The converter recognizes the selection of STO via
2. The converter interrupts the energy supply to the
3. The converter signals that "STO is active" via a
Functionality of STO when the motor is at standstill (A) and rotating (B)
If the motor is still rotating (B) when STO is selected, then it coasts down to standstill.
The STO safety function is standardized
The STO function is defined in IEC/EN 61800-5-2:
"[...] [The converter] does not supply any energy to the motor which can generate a torque
(or for a linear motor, a force)."
⇒ The STO converter function is in conformance to IEC/EN 61800-5-2.
234
Safe Torque Off (STO)
a safety-relevant input or via the PROFIsafe safe
communication.
motor.
safety-relevant output or via the PROFIsafe safe
communication.
Standard converter functions linked with STO
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If you use a motor holding brake, the converter
closes the brake.
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SINAMICS G115D Wall Mounted distributed drive
Operating Instructions, 07/2023, FW V4.7 SP14, A5E52808211A AA