Siemens SINAMICS S120 Function Manual page 69

Difference between Safe Stop 1 with and without an encoder
The SS1 function with an encoder monitors whether motor acceleration reaches
impermissible levels during the SS1 time. If the drive complies with acceleration monitoring
limits, STO is triggered when the shutdown speed is reached. If acceleration monitoring
limits are violated, messages C01706 and C30706 are output and the drive is stopped with
STOP A. If the motor does not reach the shutdown speed within the set braking time, STO is
still triggered and the drive coasts to a standstill. No message is issued.
The SS1 function without an encoder is a monitoring facility for ensuring the motor does not
exceed the set brake ramp. STO is triggered when the speed drops below the shutdown
speed. If the set brake ramp is violated (exceeded), messages C01706 and C30706 are
output and the drive is stopped with STO (STOP A).
Parameterization of the encoderless brake ramp
p9581/p9381 and p9583/p9383 are used to set the steepness of the brake ramp.
Parameters p9581/p9381 determine the reference speed and parameters p9583/p9383
define the monitoring period. Parameters p9582/p9382 are used to set the time between the
triggering of Safe Stop 1 and the start of brake ramp monitoring.
Restrictions
The following restrictions apply to the encoderless SS1 and encoderless SLS functions:
Safety Integrated
Function Manual, (FHS), 11/2009, 6SL3097-4AR00-0BP0
Cannot be used in conjunction with
1 SINAMICS chassis and cabinet formats
2 Synchronous motors
3 Torque control
4 SW gating unit
Cannot be used in conjunction with the following functions
1 Motor identification
2 Rotating measurement
3 Flying restart
4 Pole position identification
5 Vdc controller
6 DC braking
7 Measurement functions (frequency response measurement)
8 Current limitation (I )
Lim
Safety Integrated Extended Functions
5.3 Safe Stop 1 (SS1)
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