Safe Stop 2 (Ss2) - Siemens SINAMICS S120 Function Manual

● p9560 SI motion pulse cancelation shutdown speed (Control Unit)
● r9722 CO/BO: SI motion, status signals
4.2

Safe Stop 2 (SS2)

Description
The Safe Stop 2 (SS2) function is used to safely brake down the drive along the OFF3 ramp
(p1135), with transition to the SOS state (refer to the chapter Safe Operational Stop) on
expiration of the delay time (p9352/p9552). The delay time set must allow for the drive to
brake down to a standstill within this time. The standstill tolerance (p9330/p9530) may not be
violated after this time.
After the braking operation is completed, the drives remain in speed control mode (speed
setpoint n = 0). The drive is not disconnected from hazardous voltage. The default setpoint
(e.g from the setpoint channel, or from a higher-level control) remains inhibited as long as
SS2 is selected. The Safe Acceleration Monitor (SBR) function is active within the ramp
down phase.
Figure 4-2
Responses
Speed limit violated (SBR):
● STOP A
● Safety message C01706/C30706
Standstill tolerance violated in p9330/p9530 (SOS):
● STOP B with subsequent STOP A
● Safety message C01707/C30707
System errors:
● STOP F with subsequent STOP A
Safety Integrated
Function Manual, (FHS) , 07/2007 Edition, 6SL3097-2AR00-0BP0
Sequence with SS2 selection
Extended Functions
4.2 Safe Stop 2 (SS2)
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