Siemens SINAMICS G120 Function Manual page 214

Operation
6.7 Safe Speed Monitor (SSM)
The feedback signal "SSM active" for pulse inhibit remains active
With this setting, you must maintain a certain sequence before switching on the motor.
Procedure
To switch the motor on, proceed as follows:
1. Select STO (or SS1) after the motor has been switched off.
2. Deselect STO (or SS1) again before you switch on the motor.
3. After deselecting STO, wait until the inverter is "ready to switch on".
Alternatively: After deselecting STO, wait a certain time before switching on. We
recommend a wait time of 200 ms.
4. Switch on motor within 5 s after deselecting STO (ON command).
Figure 6-38
You have switched on the motor.
You have not switched on the motor within 5 seconds
If you do not switch on the motor within 5 seconds after deselecting STO, the following
happens:
● The inverter goes back into the STO state.
● The inverter no longer responds to the ON command.
● The inverter outputs Alarm A01795.
To switch on the motor you must repeat the procedure described above.
214
Switching on the motor when SSM is active
Safety Integrated - SINAMICS G110M, G120, G120C, G120D and SIMATIC ET 200pro FC-2
Function Manual, 04/2014, FW V4.7, A5E34261271B AA