Siemens SINAMICS S120 Function Manual page 593

Selecting/deselecting "Safe Torque Off"
The following is executed when "Safe Torque Off" is selected:
● Each monitoring channel triggers safe pulse suppression via its switch-off signal path.
● A motor holding brake is closed (if connected and configured).
Deselecting "Safe Torque Off" represents an internal safety acknowledgement. The following
is executed if the cause of the fault has been removed:
● Each monitoring channel cancels safe pulse suppression via its switch-off signal path.
● The Safety requirement "Close motor holding brake" is canceled. A motor holding brake
● Any pending STOP F or STOP A commands are canceled (see r9772 / r9872).
● The messages in the fault memory must also be reset using the general
Restart after the "Safe Torque Off" function has been selected
1. Deselect the function.
2. Set drive enables.
3. Cancel the "switching on inhibited" and switch the drive back on.
Status for "Safe Torque Off"
The status of the "Safe Torque Off" (STO) function is displayed using the parameters r9772,
r9872, r9773 and r9774.
As an alternative, the status of the functions can be displayed using the configurable
messages N01620 and N30620 (configured using p2118 and p2119).
Drive functions
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
is closed by the Safe Brake Control (SBC) function (if connected and configured)."
acknowledgement mechanism.
Note
No message during selection/deselection within p9650/p9850
If "Safe Torque Off" is selected and deselected through one channel within the time in
p9650/p9850, the pulses are suppressed without a message being output.
However, if you want a message to be displayed, then you must reconfigure
N01620/N30620 as an alarm or fault using p2118 and p2119.
– 1/0 edge at input signal "ON/OFF1" (cancel "switching on inhibited")
– 0/1 edge at input signal "ON/OFF1" (switch on drive)
Safety Integrated basic functions
10.4 Safe Torque Off (STO)
593