Siemens SINAMICS G120C User Manual

Function description
Table 8-41 Principle of operation of STO
 Safe Torque O󹪜 (STO) Standard converter functions linked with STO
1. The converter identi󹪝es when STO is selected via
a failsafe digital input or via PROFIsafe.
---
2. The converter interrupts the energy supply to the
motor.
If you use a motor holding brake, the converter
closes the motor holding brake.
If you use a line contactor, the converter opens
the line contactor.
3. The converter signals "STO is active" via a failsafe
digital output or via PROFIsafe.
---
6SHHG
6HOHFW672
672LVDFWLYH
6HOHFW672
672LVDFWLYH
6SHHG
W
W
W
W
W
W
%$
Figure8-27 STO when the motor is at standstill (A), and rotating (B)
(A): When selecting STO, if the motor is already stationary (zero speed), then STO prevents
the motor from starting.
(B): If the motor is still rotating (B) when STO is selected, it coasts down to standstill.
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 conforms to IEC/EN 61800-5-2.
Example
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 time of machine components.
Application Possible solution
When the EMERGENCY STOP button is
pressed, it is not permissible for a sta‐
tionary motor to inadvertently acceler‐
ate.
• Connect the EMERGENCY STOP pushbutton with a failsafe
converter digital input.
• Select STO via the failsafe digital input.
A central EMERGENCY STOP button
must prevent the unintentional acceler‐
ation of several motors that are at a
standstill.
• Evaluate the EMERGENCY STOP button in a central control.
• Select STO via PROFIsafe.
Advanced commissioning
8.16Safe Torque O󹪜 (STO) safety function
SINAMICS G120C Converters
256 Operating Instructions, 02/2023, FW V4.7 SP14, A5E34263257B AK

Siemens SINAMICS G120C Specifications

General

Communication Interfaces	PROFINET, PROFIBUS, USS, Modbus RTU
Protection Class	IP20
Ambient Temperature	-10°C to +50°C
Storage Temperature	-40°C to +70°C
Power Range	0.55 kW to 132 kW
Voltage Range	380 V to 480 V
Output Voltage	0 V to Supply Voltage
Frequency Range	0 Hz to rated output frequency
Control Modes	Vector control with encoder
Protection	Overload, overvoltage, undervoltage, short circuit, ground fault
Relative Humidity	5% to 95%, non-condensing
Altitude	Up to 2000 m without derating