Safe Stop 1, Ss1; Basic Principle Of Operation; Dynamic Response Of Ss1 - Siemens SINAMICS G120 Function Manual

2.5

Safe Stop 1, SS1

2.5.1

Basic principle of operation

Safety function SS1 brakes the motor until it virtually reaches a standstill and monitors load
speed during the braking operation using the SBR function (Safe Brake Ramp). If the speed
is low enough, the inverter cuts off the motor torque.
SS1 monitors the speed but not the direction of rotation.
Figure 2-3
2.5.2

Dynamic response of SS1

The inverter monitors the load speed. To enable the inverter to calculate the load speed from
the motor speed, you have to parameterize the gear ratio and the number of motor pole
pairs.
SS1 functions as follows:
● The operator selects the SS1 safety function via a fail-safe input or via PROFIsafe (safe
Safety Integrated Function Manual, SINAMICS G120
Function Manual, 07/2010, FW 4.3.2, A5E03052391B AA
Basic principle of operation of SS1
bus communication).
– If the motor torque has already been cut off when SS1 is selected, the inverter safely
switches off the motor torque (STO).
– If the motor is switched on when SS1 is selected, the inverter brakes the motor with
the OFF3 ramp-down time. The OFF3 ramp-down time is set with parameter P1135.
Note
The motor is decelerated until it reaches a standstill. The braking of the motor cannot
be interrupted by deselecting SS1 during braking.
Description
2.5 Safe Stop 1, SS1
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