Siemens SINAMICS G115D Operating Instructions Manual page 191

The STO function is suitable for achieving an emergency stop but not an emergency off.
Risk:
Measure to minimize
risk:
Command:
Classic solution:
Solution with the STO
safety function inte-
grated in the drive:
Application examples for the STO function
The STO function is suitable for applications where the motor is already at a standstill or will
come to a standstill in a short, safe period of time through friction. STO does not shorten the
run-on of machine components with high inertia.
Examples
When the Emergency Stop button is pressed, a
stationary motor should not unintentionally start.
A central emergency stop button must prevent the
unintentional acceleration of several motors that
are at a standstill.
SINAMICS G115D distributed drive
Operating Instructions, 09/2020, FW V4.7 SP13, A5E48681219B
Risk of electric shock:
Safe switch off
Switching off the electric power sup-
ply for the installation, either com-
pletely or partially.
Emergency Off
Switch off the power supply:
STO is not suitable for safely switch-
ing off an electric voltage.
Advanced commissioning
6.13 Safe Torque Off (STO) safety function
Risk of unexpected motion:
Safely stop and safely prevent re-
starting
Stopping or preventing the dangerous
movement
Emergency Stop
Switch off the drive power supply:
Select STO:
It is permissible that you switch of the
converter supply voltage as well.
However, switching off the voltage is
not required as a risk-reduction
measurement.
Possible solution
• Wire the Emergency Stop button to a fail-
safe input of the converter.
• Select STO via the fail-safe input.
• Evaluate the Emergency Stop button in a
central control.
• Select STO via PROFIsafe.
189