Siemens SINAMICS V90 Operating Instructions Manual page 246

Safety Integrated function
9.4 Safety Integrated basic function
● When the "Safe Torque Off" function is selected, the following applies:
– The motor cannot be started accidentally.
– The pulse suppression safely disconnects the torque-generating energy feed to the
– The power unit and motor are not electrically isolated.
● By selecting/deselecting STO, the safety messages are automatically withdrawn.
The STO function can be used wherever the drive naturally reaches a standstill due to load
torque or friction in a sufficiently short time or when "coasting down" of the drive will not have
any relevance for safety.
Personal injury or device damage resulting from the unexpected movement of the motor
after the energy feed is disconnected
The motor may have an unexpected move once the energy feed has been disconnected.
This may lead to a personal injury or device damage.
• Take appropriate measures to ensure that the motor does not undesirably move in this
Personal injury or device damage resulting from the simultaneous failure of two power
transistors in the inverter
If two power transistors (one in the upper and one in the lower bridge) simultaneously fail in
the drive, this can cause brief momentary movement. For a synchronous rotary motor, the
maximum movement is 180 °/Number of pole pairs. For a synchronous liner motor, the
maximum movement is the pole width.
• Take suitable measures to prevent unexpected drive movement, for example, by using a
Note
Closing delay of the holding brake
The closing signal (low level) of the holding brake is output 30 ms after the STO is triggered.
Preconditions for using the STO function
When use the STO function, the following preconditions must be fulfilled:
● The high level duration of the input pulse is larger than 500 ms.
Note
If the input signal contains pluses whose high level duration are less than 500 ms, you
need to decrease the sensitivity of the STO sensor or filter the input pulses by a PLC
program or by a physical filter.
244
motor.
WARNING
case, e.g. against coasting down.
CAUTION
brake equipped with safety monitoring.
SINAMICS V90, SIMOTICS S-1FL6
Operating Instructions, 04/2020, A5E37208830-008