Siemens SINAMICS S120 Function Manual page 592

Safety Integrated basic functions
10.4 Safe Torque Off (STO)
Danger through brief momentary movements
If two power transistors simultaneously fail in the power unit (one in the upper and one in
the lower inverter bridge), then this can cause brief momentary movement.
The maximum movement can be:
• Synchronous rotary motors: Max. movement = 180° / no. of pole pairs
• Synchronous linear motors: Max. movement = pole width
Enabling the "Safe Torque Off" function
The "Safe Torque Off" function is enabled via parameter p9601:
● STO for the Safety Integrated Basic Functions:
– p9601 = 1 hex (Basic Functions via onboard terminals)
– p9601 = 8 hex (Basic Functions via PROFIsafe)
– p9601 = 9 hex (Basic Functions via PROFIsafe and onboard terminals)
● STO via PROFIsafe:
– p9601.0 = 0, p9801.0 = 0
– p9601.2 = 0, p9801.2 = 0
– p9601.3 = 1, p9801.3 = 1
● STO via PROFIsafe and terminals:
– p9601.0 = 1, p9801.0 = 1
– p9601.2 = 0, p9801.2 = 0
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WARNING
– p9601.3 = 1, p9801.3 = 1
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
Drive functions