Siemens SINAMICS G115D

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.
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Principle of operation of STO
 Safe Torque O󹪜 (STO) Standard converter functions linked with STO
1. The converter recognizes the selection of STO via
a safety-relevant input or via the PROFIsafe safe
communication.
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2. The converter interrupts the energy supply to the
motor.
If you use a motor holding brake, the converter
closes the brake.
3. The converter signals that "STO is active" via a
safety-relevant output or via the PROFIsafe safe
communication.
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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.
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The STO safety function is standardized
The STO function is de󹪝ned 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.
Advanced commissioning
7.15Safe Torque O󹪜 (STO) safety function
SINAMICS G115D Wall Mounted distributed drive
234 Operating Instructions, 07/2023, FW V4.7 SP14, A5E52808211A AA