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

5.4

Safe Stop 2 (SS2)

General description
The "Safe Stop 2" (SS2) function is used to brake the motor safely along the OFF3
deceleration ramp (p1135) with subsequent transition to the SOS state (see "Safe Operating
Stop") after the delay time expires (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 the speed control mode with
the speed setpoint n = 0.
The safety function "Safe Stop 2" (SS2) can only be used with an encoder.
For SS2, the full rated voltage is available at the motor (V
the motor.
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
selected during braking.
Figure 5-3
Note
If SS2 is activated, this can cause the device (PLC, motion controller) which specifies the
speed setpoint to interrupt the ramp function with OFF2.
The reason is a fault response of this device, which is initiated when OFF3 is activated.
The fault response can be prevented using suitable parameterization or wiring, which then
signals the initiation of SS2 to this device.
Safety Integrated
Function Manual, (FHS), 11/2009, 6SL3097-4AR00-0BP0
WARNING
Sequence with SS2 selection
Safety Integrated Extended Functions
5.4 Safe Stop 2 (SS2)
) and current flows through
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