Description Of A Dp Cycle - Siemens SINUMERIK 840Di Manual

06.03
7.1.2

Description of a DP cycle

Actual values
Position controller
Setpoints
NC:
Master or position
controller
PROFIBUS DP
communication
Speed
controller cycle
Drives:
DP slave: 1 to 3
Fig. 7-2 Example: Optimized DP cycle with 3 DP slaves 611U
 Siemens AG, 2003. All rights reserved
SINUMERIK 840Di Manual (HBI) – 06.03 Edition
At the time T , all equidistant drives (DP slaves) read in the current actual posi-
I
tion values. In the next DP cycle, at time T
to the DP master.
At the time T with T > T
M, M
the new speed setpoints using the actual position values transferred.
At the beginning of the next DP cycle at time T
ferred from DP master to the DP slaves (drives).
At the time T , the speed setpoints are accepted by all servo drive controls as
O
the new default.
T
M
T
DX
1
DPV1 RGT GC Dx Dx
R R R R R
T
O
T
I
Explanations regarding Fig. 7-2:
T Master Application Cycle: NC position controller cycle
MAPC
With SINUMERIK 840Di, the following applies in all cases: T
T DP cycle time: DP cycle time
DP
T Data Exchange Time: Total of transfer times of all
DX
DP slaves
7 PROFIBUS DP Communication
, the actual values are transferred
DX
the NC position controller is started, calculating
DX,
, the speed setpoints are trans-
DX
T T
MAPC = DP
R
T
Dx DPV1 RGT GC Dx
R R R R R R
TI
7.1 General
DX
2
Dx Dx
R R R R R
T
O
= T
MAPC
7-205
DP