NC Commissioning with HMI Advanced
11.3 System data
Manual
Commissioning Manual, 05/2008, 6FC5397–4CP10–4BA0
375
11.3.8
Cycle times
On the SINUMERIK 840Di sl, the system clock cycle, the position controller cycle and the
interpolation cycle of the NC are based on the DP cycle time configured in STEP 7 "HW
Config" (see Section "Create SIMATIC S7 Project" (Page 160)).
Basic system cycle
The DP cycle time configured in STEP 7 is taken over as the system clock cycle and
displayed in the following machine data:
●
MD10050 $MN_SYSCLOCK_CYCLE_TIME (system clock) = DP cycle time
Note
The DP cycle time configured in STEP 7 "HW Config" is only taken as the system clock
cycle from the NC if at least one real machine axis is parameterized in the NC machine
data.
If no real machine axis is parameterized, the value of the machine data functions as the
system clock cycle:
•
MD 10050 $MN_SYSCLOCK_CYCLE_TIME
Position controller cycle
The ratio of position controller cycle to system clock cycle for SINUMERIK 840Disl is always
1:
●
MD10060 $MN_POSCTRL_SYSCLOCK_TIME_RATIO = 1
Note
The machine data is not displayed for SINUMERIK 840Di sl.
Position controller cycle offset
The position controller cycle offset (T
M
) must be set so that the following conditions are
fulfilled within a DP cycle (T
DP
):
●
Cyclic communication with the DP slaves (drives) must be completed before the position
controller is started.
Condition: T
M
> T
DX
●
The position controller must be completed before the DP cycle is completed.
Condition: T
M
+ T
Pos
< T
DP
The following setting is recommended as approximate value for the position control cycle
offset:
T
M
= T
DP
- 3*T
pos max
●
T
DP
The DP cycle time is equivalent to the position controller cycle of the SINUMERIK 840Di
sl.
●
T
Pos max
Display via HMI Advanced (option):
Operating area switchover > Diagnosis > Service Displays > System Resources
