Safe Torque Off (Sto) - Siemens Sinamics S120 Function Manual

The "automatic restart" function may not be used together with the safety functions
STO/SBC and SS1. The reason for this is that EN 60204 Part 1 (1998) in chapter 9.2.5.4.2
does not permit this (merely de-selecting a safety shutdown function must not cause the
machine to restart).
NOTICE
Components cannot be deactivated via p0105, for example, with activated Safety functions.
9.4

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 energy feed to the motor.
When the function is selected, the drive unit is in a "safe status". 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 a basis for this function.
Functional features of "Safe Torque Off"
● This function is integrated in the drive; this means that a higher-level controller is not
● The function is drive-specific, i.e. it is available for each drive and must be individually
● The function must be enabled using parameters.
● When the "Safe Torque Off" function is selected, the following applies:
● Extended acknowledgment:
Drive functions
Function Manual, (FH1), 01/2012, 6SL3097-4AB00-0BP2
CAUTION
required.
commissioned.
– The motor cannot be started accidentally.
– The pulse suppression safely disconnects the torque-generating energy feed to the
motor.
– The power unit and motor are not electrically isolated.
If STO is selected/deselected (and p9307.0/p9507.0 = 1 are set), then the safety
messages are withdrawn automatically.
If, in addition to the "Extended Functions", the "Basic Functions via terminals" are also
enabled, then in addition to selecting/deselecting STO via PROFIsafe or TM54F,
acknowledgment is also possible by selecting/deselecting STO via terminals; whereby
only messages of the stop responses STOP C, STOP D, STOP E and STOP F can be
acknowledged, as long as STOP A or STOP B has not been initiated.
Safety Integrated basic functions
9.4 Safe Torque Off (STO)
463