Siemens SINUMERIK 840D sl Function Manual page 190

G3: Cycle times
3.4 SINUMERIK 840Di with PROFIBUS DP
Alarm requests in the event of a conflict during startup
MD10059 $MN_PROFIBUS_ALARM_MARKER (PROFIBUS alarm marker)
In this machine data, alarm requests on the PROFIBUS level are stored even after reboot.
If a conflict is found between the following machine data and the data in the PROFIBUS-SDB
during the booting, the machine data is adjusted to this SDB and an alarm is set during the
next booting:
MD10050 $MN_SYSCLOCK_CYCLE_TIME (system clock cycle)
MD10060 $MN_POSCTRL_SYSCLOCK_TIME_RATIO (factor for position-control cycle)
MD10070 $MN_IPO_SYSCLOCK_TIME_RATIO (factor for the interpolation cycle)
Points to note
The following special points must be observed for cycle-specific machine data:
• MD10050 $MN_SYSCLOCK_CYCLE_TIME (system clock cycle)
The machine data is simply for display purposes. The system cycle is always equal to the
equidistant PROFIBUS-DP cycle.
• MD10060 $MN_POSCTRL_SYSCLOCK_TIME_RATIO (factor for position-control cycle)
The factor for the position-control cycle is set at a fixed value of 1 and cannot be modified.
If you change the cycle times, check the behavior of the controller in all operating modes
before you finish commissioning.
Note
The smaller the cycle times (PROFIBUS DP cycle) chosen, the greater the control quality
for the drive and better the surface quality on the workpiece.
190
CAUTION
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
Special Functions