Siemens SINAMICS S120 Function Manual page 55

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:
● Each monitoring channel cancels safe pulse suppression via its switch-off signal path.
● The Safety requirement "Close motor holding brake" is canceled.
● Any pending STOP F or STOP A commands are canceled (see r9772 / r9872).
● The cause of the fault must be removed.
● The messages in the fault memory must be additionally reset using the general
Restart after the "Safe Torque Off" function has been selected
1. Deselect the function in each monitoring channel via the input terminals.
2. Issue drive enable signals.
3. Cancel the "switching on inhibited" and switch the drive back on.
4. Operate the drives again.
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).
Response time for the "Safe Torque Off" function
For the response times when the function is selected/deselected via input terminals, see the
table in "Response times".
Safety Integrated
Function Manual, (FHS), 11/2009, 6SL3097-4AR00-0BP0
acknowledgement mechanism.
Note
If "Safe Torque Off" is selected and de-selected 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
4.1 Safe Torque Off (STO)
55