Siemens SINAMICS S120 - Page 823

Communication
11.3 Communication via PROFINET IO
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
823
Sequence of data transfer to closed-loop control system
1. Actual position value G1_XIST1 is read into the telegram image at time T
IO_Input
before the
start of each cycle and transferred to the controllers in the next cycle.
2. Closed-loop control of the controller starts at time T
CA_Start
after each position controller
cycle and uses the current actual values read previously from the devices.
3. In the next cycle, the controller transfers the calculated setpoints to the telegram image of
the devices. The speed setpoint command NSET_B is issued to the closed-loop control
system at time T
IO_Output
after the beginning of the cycle.
Note
With the isochronous telegram setting, the complete SI
NAMICS device is in clock cycle
synchronism with all data. Reasons:
•
Between the controller and device, all data are only exchanged in one IRT frame.
•
In SINAMICS, all data are consistently processed in synchronism.
Designations and descriptions for motion control
Table 11- 15 Time settings and meanings
Name
Limit value
Description
T
DC_BASE
- Time basis for cycle time T
DC
calculation:
T
DC_BASE
= T_DC_BASE · 31.25 µs = 4 · 31.25 µs = 125 µs
T
DC
T_DC_MIN ≤ T_DC ≤
T_DC_MAX
Cycle time
T
DC
= T_DC · T
DC_BASE
,T_DC: integer factor
CBE20:
T
DC_MIN
= T_DC_MIN · T
DC_BASE
= 4 · 125 µs = 500 µs
T
DC_MAX
= T_DC_MAX · T
DC_BASE
= 32 · 125 µs = 4 ms
X150 (CU3x0-2 PN):
T
DC_MIN
= T_DC_MIN · T
DC_BASE
= 2 · 125 µs = 250 µs
T
DC_MAX
= T_DC_MAX · T
DC_BASE
= 32 · 125 µs = 4 ms
T
CACF
CACF = 1-14 IO controller application cycle time
This is the time frame in which the IO controller application generates new
setpoints (e.g. in the position controller cycle).
Calculation example:
T
CACF
= CACF · T_DC = 2 · 500 µs = 1 ms
T
CA_Valid
T
CA_Valid
< T
DC
Time, measured from the beginning of the cycle, at which the actual val-
ues of all IO devices for the controller application process (position con-
trol) are available.
T
CA_Start
T
CA_Start
> T
CA_Valid
Time, measured from the beginning of the cycle, at which the controller
application process (position control) starts.
T
IO_BASE
Timebase for T
IO_Input
, T
IO_Output
T
IO_BASE
= T_IO_BASE · 1 ns = 125000 · 1 ns = 125 µs