Independent, Timer-Controlled Output Of Cam Signals - Siemens SINUMERIK 840D sl Function Manual

PLC interface
The NCK image of the onboard outputs and the status of the plus and minus cams is displayed
on the PLC interface.
However, these signals are irrelevant or correspondingly inaccurate for the timer-controlled
cam output version, as described in the following paragraphs. The signals for the plus and
minus cams are generated (once) in synchronism with the interpolator clock cycle and
transmitted together to the PLC.
Pulses shorter than an interpolator clock cycle are therefore not visible in the PLC.
The onboard outputs are set and reset asynchronously to the interpolator clock cycle for each
interrupt. The status of the onboard outputs is detected and transmitted to the PLC in
synchronism with the update time of the PLC interface.
Depending on the current status at the moment the PLC interface is updated, pulses shorter
than one interpolator clock cycle are not visible or are displayed stretched by one or several
IPO cycles.
Further settings
The following bit must be set to "0" if the behavior described here is to be activated:
MD10485 SW_CAM_MODE bit 0 = 0
9.3.5

Independent, timer-controlled output of cam signals

Independent, timer-controlled cam output
Each switching edge is output separately per interrupt due to the timer-controlled, independent
(of interpolator clock cycle) cam output.
The mutual influence of the cam signals is no longer applicable as a result of:
● single output per interpolator clock cycle
● output time determined by highest priority cam pair (lowest cam pair number)
A total of 8 timer-controlled cam outputs per interpolator clock cycle can be configured for
setting/resetting the 4 onboard outputs. The signal states of the plus and minus cams are also
made available as standard on the PLC interface for the timer-controlled variant. However,
these signals are not relevant or are correspondingly inaccurate with a timer-controlled output.
Signal generation
Previously, it had to be specified in which way the signals to be logically combined should be
generated. This is realized using bit 1 in machine data:
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
N3: Software cams, position switching cycles - only 840D sl
9.3 Output of cam signals
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