Siemens SINAMICS S120 Function Manual page 51

Example of how the function can be used
Example
A protective door must only be opened if a motor is
in the safe standstill state.
How does SS2 function in detail?
The safety function SS2 monitors the
load speed and initiates the SOS function
if the SS2 delay time has expired.
With SS2, braking is monitored on the
OFF3 ramp. A faulty acceleration is de-
tected and the drive then shuts down
with STO.
If you are operating the motor with closed-loop torque control, the converter switches to the
closed-loop speed control mode when SS2 is selected.
Detailed description
The failsafe logic (e.g. F-CPU) selects the SS2 safety function via a failsafe input or via the
PROFIsafe safe communication.
● If, when selecting SS2, the motor is already at a standstill, after a delay time, the
converter activates the Safe Operating Stop function (SOS).
● If the drive is not at standstill when SS2 is selected, it is braked along the OFF3 ramp.
Braking is monitored with one of the following functions, depending on the setting in
p9506:
– "Safe Acceleration Monitor (SAM)"
– "Safe Brake Ramp (SBR)"
After a delay time, the converter activates the Safe Operating Stop function (SOS). This
function monitors the safe standstill of the drive.
Safety Integrated
Function Manual, 12/2018, 6SL3097-5AR00-0BP1
A faulty acceleration is therefore detected.
In this way, a violation of the braking ramp is detected.
Overview of Safety Integrated functions
3.2 Safety Integrated Extended Functions
Possible solution
Select SS2 in the converter via a terminal or
•
via PROFIsafe .
After braking, the converter goes into the
•
SOS state. Only then may the protective
door be released.
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