Timer-Controlled Cam Signal Output - Siemens SINUMERIK 840D Function Manual

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 NC I/O or onboard outputs in the position control cycle.
As a result of the time scale of the position control cycle, the switching accuracy of the cam
signals is limited as a function of the velocity.
The following applies:
Delta pos = V
With:
Example:
V
act
V
act
13.3.4

Timer-controlled cam signal output

Timer-controlled output
A significantly higher degree of accuracy can be achieved by outputting the cam signals
independently of the position control cycle using a timer interrupt.
The following machine data can be used to select the timer-controlled output to the 4 NCU
onboard outputs for 4 cam pairs:
MD10480 SW_CAM_TIMER_FASTOUT_MASK (screen form for the output of cam signals via
timer interrupts on the NCU)
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
* position control cycle
act
Delta pos = switching accuracy (depending on position control cycle)
V = Current axis velocity
act
= 20 m/min, PC cycle = 4 ms
= 2000 rpm, PC cycle = 2 ms
N3: Software cams, position switching signals
13.3 Output of cam signals
Delta pos = 1.33 mm
Delta pos = 24 degrees
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