Siemens SINUMERIK 840D sl Function Manual page 725

Writing/reading of cam positions
The setting data can be read and written via HMI, PLC and part program.
Accesses from the part program are not synchronous to machining.
Synchronization can only be achieved by means of a programmed block preprocessing stop
(STOPRE command).
It is possible to read and write the cam positions with FB2 and FB3 in the PLC user program.
Axis/cam assignment
A cam pair is assigned to a machine axis using general machine data:
MD10450 SW_CAM_ASSIGN_TAB[n]
(assign software cams to machine axes).
Note
Changes to an axis assignment take effect after the next NCK power-up.
Cam pairs to which no axis is assigned are not active.
A cam pair can only be assigned to one machine axis at a time.
Several cam pairs can be defined for one machine axis.
9.2.4 Lead/delay times (dynamic cam)
Times
To compensate for any delays, it is possible to assign two lead or delay times with additive
action to each minus and plus cam for the cam signal output.
The two lead or delay times are entered in a machine data and a setting data.
Note
The input of negative time values causes a delay in the output of cam signals.
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Software Cams, Position Switching Signals (N3)
Cam signals and cam positions
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