Siemens Sinumerik 840D sl Function Manual page 150

Safety functions integrated in the system/drive
6.4 Safe acceleration monitoring (SBR)
Table 6-10 Explanation of the figure, continued
Time Explanation
t Time until a limit value violation is detected
4
(typical 1 monitoring clock cycle, maximum 1.5 monitoring clock cycles + 1 position controller
clock cycle)
t Response time that is required to introduce the stop response
5
(typical 2 monitoring clock cycles, maximum 2.5 monitoring clock cycles + 1 position controller
clock cycle)
t Time until the stop response that was initiated starts
6
(typical 2 ms, maximum 3 position controller clock cycles + 8 ms)
t Time required to bring the axis to a standstill.
7
This time and thus the residual distance traveled by the axis is determined by the axis design
(motor, mass, friction, ...).
Note
During "normal" operation, speed overshoot should not unintentionally initiate the
SBR. Speed overshoot should therefore be checked by making the appropriate
measurements.
Warning
!
If the safe standstill function or "STOP A" is activated, the motor can no longer
generate any torque. This is the reason that potentially hazardous motion can
occur, e.g. for the following:
S When an external force acts on the drive axes
S Vertical and inclined axes without weight equalization
S Axes that are moving (coasting down)
S Direct drives with low friction and low self--locking
S Notching torques (depending on the motor type, bearing design and friction
characteristics, up to half a pole pitch in a direction that cannot be predicted)
Possible hazards must be clearly identified using a risk analysis that must be
carried out by the manufacturer. With an assessment, based on this risk analysis,
it should be defined as to which additional measures are required, e.g. external
brakes.
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
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