Functional Description - Siemens SINUMERIK 840D sl Function Manual

TE9: Axis pair collision protection

17.2 Functional description

17.2 Functional description
The "axis pair collision protection" function is a protection function for machine axes which are
arranged in a machine tool in such a way (on the same guide rail, for example) that incorrect
operation or programming could cause them to collide with one another.
The machine axes are always monitored in pairs, i.e. parameters always need to be assigned
for two machine axes in each case, which are then monitored in relation to one another. The
machine axes being monitored may be located in different machine coordinate systems.
Collision protection
The function uses the current actual positions and actual velocities, as well as the offset for
the machine coordinate systems and the axis-specific brake acceleration values, to calculate
the distance between the standstill positions of the machine axes, on a cyclical basis. If the
resulting distance is shorter than the protection window that has been set, the machine axes
are decelerated to a standstill. This ensures that the minimum distance defined using the
protection window is not undershot.
Distance monitoring
If the offset vector is selected accordingly, the function can also be used to monitor the
maximum distance between the two machine axes (maximum distance vector).
Figure 17-1 Basic design
Monitoring status
The current status of a pair of machine axes can be read from an item of global user data
(GUD), which you must define in the NC program if you wish to make use of this option.
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Function Manual, 09/2011, 6FC5397-2BP40-2BA0
Special Functions