Safe Torque Off (Sto) - Siemens Sinumerik 840D sl Function Manual

Safety Functions integrated in the drive

4.3 Safe Torque Off (STO)

4.3 Safe Torque Off (STO)
In conjunction with a machine function or in the event of a fault, the "Safe Torque
Off (STO)" function is used to safely disconnect the torque--generating power feed
to the motor.
After selecting the function, the drive device is in a "Safe state". The switching on
inhibited function prevents the drive unit from being restarted.
The two--channel pulse suppression function integrated in the Motor Modules /
Power Modules is the basis for this function.
Functional features of Safe Torque Off
S This function is integrated in the drive, i.e. a higher--level control is not required.
S The function is drive specific. This means that each drive has the function and it
must be individually commissioned.
S The function must be enabled using a parameter.
S When the Safe Torque Off function is selected, the following applies:
-- The motor cannot be started accidentally.
-- The safety--related pulse suppression safely disconnects the torque--genera-
ting energy supply to the motor.
-- the power unit and motor are not electrically isolated.
S The selection/deselection of the STO function also acknowledges the safety
faults when the Basic Functions are used. The standard acknowledgment me-
chanism must also be performed.
S The signals of the components connected at the terminals (e.g. pushbuttons,
switches, ...) can be debounced in order to prevent false tripping due to signal
disturbances. The filter times are set via parameters p9651 and p9851.
Warning
!
Undesirable motor motion
Appropriate measures must be taken to ensure that the motor does not move
once the motor power supply has been disconnected ("coast down") (e.g. enable
the "Safe brake control" function for a vertical axis).
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
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