Siemens SINAMICS S120 Function Manual page 310

Safety Integrated basic functions
9.3 Safe Torque Off (STO)
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. Revoke the closing lockout and switch the drive back on.
4. Run the drives again.
Status for "Safe Torque Off"
The status of the "Safe Torque Off (STO)" function is displayed using the following
parameters:
Parameter overview (see List Manual)
● r9772 CO/BO: SI status (Control Unit)
● r9872 CO/BO: SI status (Motor Module)
● r9773 CO/BO: SI status (Control Unit + Motor Module)
● r9774 CO/BO: SI status (Safe Torque Off group)
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 with the "Safe Torque Off" function
The following values can be specified for the response times when the function is
selected/deselected via input terminals:
● Typical response time
● Max. response time in the event of a fault
Examples, Booksize:
Assumption:
Safety monitoring clock cycle time CU (r9780) = 4 ms and
inputs/outputs sampling time (r0799) = 4 ms
t
R_typ
t
R_max
310
– 1/0 edge at input signal "ON/OFF1" (cancel power-on inhibit)
– 0/1 edge at input signal "ON/OFF1" (switch on drive)
2 x Safety monitoring cycle CU (r9780) + inputs/outputs sampling time (p0799)
4 x Safety monitoring cycle CU (r9780) + inputs/outputs sampling time (p0799)
= 2 x r9780 (4 ms) + r0799 (4 ms) = 12 ms
= 4 x r9780 (4 ms) + r0799 (4 ms) = 20 ms
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
Drive Functions