Siemens SINUMERIK 840D sl Function Manual page 591

Linear axes
The switching edges of the cam signals are generated as a function of the axis traversing
direction:
● The minus cam signal switches from 1 to 0 when the axis traverses the minus cam in the
positive axis direction.
● The plus cam signal switches from 0 to 1 when the axis traverses the plus cam in the positive
direction.
Figure 9-1
Note
If the axis is positioned exactly at the output cam position (plus or minus), the defined output
flickers. If the axis moves one increment further, the output becomes a definite zero or one.
Flickering of the actual position causes the signals to flicker in this manner.
The actual position is evaluated.
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
N3: Software cams, position switching cycles - only 840D sl
Software cams for linear axis (minus cam < plus cam)
9.2 Cam signals and cam positions
591