Functions
8.10 Safe Torque Off (STO) safety function
SINAMICS G110M Operating Instructions
Operating Instructions, 04/2015, FW V4.7.3, A5E31298649B AD
245
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.
When the Emergency Stop button is pressed, a
stationary motor should not unintentionally start.
• Wire the Emergency Stop button to a fail-
safe input of the inverter.
• Select STO via the fail-safe input.
A central emergency stop button must prevent the
unintentional acceleration of several motors that
are at a standstill.
• Evaluate the Emergency Stop button in a
central control.
• Select STO via PROFIsafe.
In order to use the STO safety function, the machine manufacturer should have already
performed a risk assessment, e.g. in compliance with EN ISO 1050, "Safety of machinery -
Principles of risk assessment". The risk assessment must confirm that the inverter is
permitted for use in accordance with SIL 2 or PL d.
Commissioning STO
8.10.3.1
We strongly recommend that you commission the safety functions using a PC tool.
Table 8- 26 PC-based commissioning tools
STARTER
(http://support.automation.siemens.com/WW/view/
6SL3072-0AA00-0AG0 Basic commissioning
with STARTER
Startdrive
(http://support.automation.siemens.com/WW/view/
en/68034568)
6SL3072-4CA02-1XG0 Tutorial
(http://support.autom
ation.siemens.com/
WW/view/en/735984