Technical data
Safety Integrated Functions
8.5 Safety Integrated Extended Functions
Function Manual
Function Manual, 06/2012, 6SL3097-4AB10-0BP4
373
8.5.4 Safe Stop 2 (SS2)
The "Safe Stop 2" (SS2) safety function is used to brake the motor safely on the OFF3 ramp
down (p1135) with subsequent transition to the SOS state (see the "Safe Operating Stop"
chapter) after the delay time expires (p9352/p9552). The delay time set must allow the drive
to decelerate 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 drive remains in the speed controlled mode with
the speed setpoint n = 0. The full torque is available.
Note
The "Safe Stop 2" (SS2) safety function can only be used with an encoder.
The setpoint input (e.g. from the setpoint channel, or from a higher-level control) remains
inhibited as long as SS2 is selected. The "Safe Acceleration Monitor" (SAM) function is
active during braking.
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Figure 8-5 Sequence with SS2 selection
Selection and monitoring of the brake ramp (SBR) or the acceleration (SAM) are
implemented in two channels, however braking along the OFF3 ramp is only through one
channel.
Note
Activating SS1 can mean that the higher-level control (PLC, motion controller), which enters
the speed setpoint, interrupts the ramp function with OFF2. The reason for this is a fault
response of this device, triggered by the OFF3 activation. This fault reaction can be avoided
using suitable parameterization/configuration.