Safe Stop 1 (Ss1) - ABB FSO-21 User Manual

68 Safety functions

Safe stop 1 (SS1)

The SS1 function stops the motor safely by ramping down the motor speed. The FSO
activates the drive STO function below a user-defined zero speed limit.
The FSO monitors the stop ramp either with the time or ramp monitoring method
(SS1 function types SS1-t and SS1-r, respectively). If the motor speed does not
follow the monitoring limit(s), the FSO activates the STO function and the motor
coasts to a stop.
The SS1 function uses SAR1 parameters to define and/or monitor the stop ramp.
When you use the SBC function with the SS1 function, you can configure the SBC
and drive STO combination to be activated at a user-defined speed limit while
ramping down to zero speed. You can also define a delay so that the SBC is activated
first at the user-defined speed limit and the drive STO after the delay.
This section describes the different versions of the SS1 function separately without
and with an encoder.