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Figure 4-5
Time-controlled output cam
Limits imposed by starting position and ON duration
The output cam is switched on:
● At the starting position.
If the starting position is overrun again during the ON duration, the time-based cam is not
switched on again. It is not possible to retrigger a time-based cam.
The output cam is switched off:
● When the assigned time period expires
● When commands are issued that deactivate the output cam, e.g. _disableOutputCam,
_setOutputCamState and _resetOutputCam
Output cam length
The output cam length is dependent on the velocity at which the assigned axis traverses during
ON duration of the output cam.
4.2.2.5
Time-based cam with maximum ON length
Additional limits imposed by maximum ON length
A maximum ON length can also be defined for time-based cams on cam tracks. This means
that the time-based cam is deactivated once it has covered the maximum length, even though
the parameterized time has not yet expired.
This is the case if, for example, glue dots should be applied to a workpiece and the amount of
glue should be independent (constant time -> time-based cam) of the throughput rate.
To avoid the time-based cam still being controlled after the end of the workpiece at high sweep
rates, the ON duration can be limited by a maximum ON length (related to the start position of
the output cam). This prevents a glue dot being placed adjacent to the workpiece.
The maximum ON length is effective in both traversing directions of the axis, and the cam
track's switch-on position is the reference position.
Parameters of a time-based cam with maximum ON length
Every time-based cam on a track has three parameters
Cam Track TO - Part II
4.2 TO Cam Track basics
Output Cams and Measuring Inputs
70
Function Manual, 04/2014