Siemens SINUMERIK 804D sl Commissioning Manual page 110

NCK start-up
10.2 System data
Interpolation cycle
The interpolator cycle may be chosen freely as a whole multiple of the position control cycle.
• MD10070 IPO_SYSCLOCK_TIME_RATIO (factor for the interpolation cycle)
Error response
• Alarm: "4240 CPU time overflow on the IPO or position controller level"
Cause of errors/error handling
The DP cycle time/position controller cycle, the interpolation cycle, or the NC CPU time
share is set in such a way that not enough CPU time is available for one of the two cyclic
levels of the NCK (position controller or interpolator).
Remedial action:
Calculate the maximum values for T
machine data:
• MD10185 NCK_PCOS_TIME_RATIO (CPU time component NCK)
• MD10070 IPO_SYSCLOCK_TIME_RATIO (factor for the interpolation cycle)
• MD10050 SYSCLOCK_CYCLE_TIME (system clock cycle)
Note
You must adjust the system clock cycle by changing the DP cycle time using STEP7
"HW-Config".
Literature
Function Manual special functions; cycly times
110
The position-control cycle offset selected is too large. The cyclic PROFIBUS
communication with the drives started before the position controller had finished. The
position controller requires more CPU time than available within the DP cycle.
– Remedy: Decrease the position-control cycle offset
Or
– Remedy: Increase the DP cycle time.
The DP cycle time is set using STEP7 "HW-Config". See Chapter "SIMATIC create S7
project".
and T (see above) and adapt the following
pos max IPO max
Commissioning Manual, 11/2006, 6FC5397-2AP10-2BA0
CNC Part 1 (NCK, PLC, drive)