Siemens Sinamics S120 Function Manual page 112

Description of Safety Integrated functions
4.2 Safety Integrated Extended Functions
Sequence diagram
The following diagram shows the signal characteristic for the case p9509.0 = 0.
Image 4-9 Safe Speed Monitor without encoder (p9509.0 = 0)
The speed remains below the limits of p9546 throughout the entire monitoring period.
Therefore, the SSM feedback signal remains r9722.15 = 1. After the command for pulse
suppression, the motor speed drops. The internal STO is set when the speed drops below
the zero speed detection level.
In this case, the SSM feedback signal remains HIGH; it is frozen. The drive cannot
accelerate again, due to the internal STO selection.
To restart the motor safely, the STO must be selected manually and deselected once more.
After the STO has been deselected, a 5 second time window is opened. If the pulse enable
takes place within this time window, the motor starts. If the pulse enable does not take place
within this 5 second time window, the internal STO becomes active once more.
If p9509.0 = 1, the SSM monitoring is ended after the pulse suppression. The feedback
signal p9722.15 drops to 0. The SSM monitoring is only reactivated after a new pulse
enable. In this case, STO must not be selected and deselected to start the drive.
112
Function Manual, (FHS), 07/2016, 6SL3097-4AR00-0BP6
Safety Integrated