Siemens Sinamics G120 Function Manual page 276

Operation
6.7 Safe Speed Monitor (SSM)
When switching off, the speed is higher than the SSM limit value
Figure 6-38 OFF1 command when the SSM safety function is active
If you switch off the motor with the SSM function active using the OFF1 or OFF3 command,
e.g. when reaching limit switches, the following happens:
1. The inverter brakes the motor down to standstill and then switches it off.
2. Also while braking, the inverter monitors the motor speed.
If the "SSM active" feedback signal should remain active when the pulses are inhibited, then
the inverter safely switches off the motor torque using the safety function STO.
276
Safety Integrated - SINAMICS G110M, G120, G120C, G120D and SIMATIC ET 200pro FC-2
Function Manual, 01/2017, FW V4.7 SP6, A5E34261271B AD