Siemens SINUMERIK 840Di sl - Page 376

NC Commissioning with HMI Advanced
11.3 System data
Manual
376 Commissioning Manual, 05/2008, 6FC5397–4CP10–4BA0
● MD10062 $MN_POSCTRL_CYCLE_DELAY (position control cycle delay) = T
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Figure 11-2 Position controller cycle offset compared to PROFIBUS DP cycle
Explanations for the figure:
T
Pos
Computing time requirements for the position controller
T
DP
DP cycle time: DP cycle time
T
DX
Data exchange time: Total transfer time for all DP slaves
T
M
Master time: Offset of the start time for NC position control
GC Global Control: Broadcast message for cyclic convergence of the
equidistance between DP master and DP slaves
R CPU time
Dx Useful data exchange between the DP master and DP slaves
MSG Acyclic services (e.g. DP/V1, pass token)
RES Reserve: "Active break" until the equidistant cycle has expired
Interpolation cycle
The interpolator cycle may be chosen freely as a whole multiple of the position control cycle.
● MD10070 $MN_IPO_SYSCLOCK_TIME_RATIO (factor for the interpolation cycle)
NC CPU time share
The processor power of the PCU must be shared between the NC and Windows XP. The
parameterized CPU time share of the NC is the maximum value that the NC will only use in
the worst case. If the NC requires less CPU time in cyclical operation, it will cede it
dynamically to Windows XP.