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

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
9.3.4

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 general machine data can be set to select 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 NCU)
In this case, the minus and plus signals of a cam pair are gated for output as one signal.
Signal generation
The following machine data must be used beforehand to specify
how the signals are to be gated:
MD10485 SW_CAM_MODE Bit 1
Bit
Not set
set
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
* 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
Signal generation
Inversion of signal response of plus cam when:
plus cam - minus cam ≥ 180 degrees
No inversion of signal response of plus cam:
plus cam - minus cam ≥ 180 degrees
9.3 Output of cam signals
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