Siemens SINUMERIK 840D sl Function Manual page 729

Note
It is possible to define one HW byte for the output of eight minus cam signals and one HW
byte for the output of eight plus cam signals in each machine data.
In addition, the output of the cam signals can be inverted with the two machine data.
If the 2nd byte is not specified (= "0"), then the 8 cams are output as a logic operation of the
minus and plus cam signals via the 1st HW byte using the 1st inversion screen form.
Status query in the part program
The status of the HW outputs can be read in the part program with main run variable
$A_OUT[n] (n = no. of output bit).
Switching accuracy
Signals are output to the NCK I/Os or onboard outputs in the position control cycle.
Owing to the time scale of the position control cycle, the switching accuracy of the cam
signals is limited as a function of velocity.
The following applies:
Delta pos = V
Delta pos:
V
act
Example:
V
act
V
act
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
* position control cycle
act
Switching accuracy (depending on position control cycle)
: Current axis velocity
= 20 m/min, PC cycle = 4 ms
= 2000 rpm, PC cycle = 2 ms
Software Cams, Position Switching Signals (N3)
Delta pos = 1.33 mm
Delta pos = 24 degrees
Output of cam signals
729