Efficient Networks Siemens Sinamics S120 - Manual (Page 417)

Communication PROFIBUS DP/PROFINET IO
10.2 Communication via PROFIBUS DP
Drive Functions
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
417
Sequence of data transfer to closed-loop control system
1. Position actual value G1_XIST1 is read into the telegram image at time T
I
before the start
of each cycle and transferred to the master in the next cycle.
2. Closed-loop control on the master starts at time T
M
after each position controller cycle
and uses the current actual values read previously from the slaves.
3. In the next cycle, the master transmits the calculated setpoints to the telegram image of
the slaves. The speed setpoint command NSOLL_B is issued to the closed-loop control
system at time T
O
after the beginning of the cycle.
Designations and descriptions for Motion Control
Table 10-31 Time settings and meanings
Name Value 1) Limit value Description
T
BASE_DP
5DC hex
≐
1500 dec
- Time basis for T
DP
calculation: T
BASE_DP
= 1500 ∙ T
Bit
= 125 µs
T
Bit
= 1/12 µs at 12 Mbaud
T
BASE_DP
corresponds to the largest current controller cycle
(p0115[0]) of a drive object (servo/vector).
T
DP
≥ T
DP_MIN
Cycle time
T
DP
= integer multiple ∙ T
BASE_DP
calculation: T
DP
= 8 ∙ T
BASE_DP
= 1 ms
T
DP
8
T
DP_MIN
= 8 Min. DP cycle time
calculation: T
DP_MIN
= 8 ∙ T
BASE_DP
= 1 ms
T
MAPC
1 n ∙ T
DP
n = 1 - 14
Master application cycle time
This is the time frame in which the master application generates
new setpoints (e.g. in the position controller cycle).
Calculation: T
MAPC
= 1 ∙ T
DP
= 1 ms
T
SAPC
Slave application cycle time
T
BASE_IO
5DC hex
≐
1500 dec
- Time basis for T
I
, T
O
calculation: T
BASE_IO
= 1500 ∙ T
Bit
= 125 µs
T
Bit
= 1/12 µs at 12 Mbaud
T
BASE_IO
corresponds to the largest current controller cycle
(p0115[0]) of a drive object (servo/vector) in the drive unit.
T
I_MIN
≤ T
I
< T
DP
Time of actual-value sensing
This is the time at which the actual position value is captured
before the start of each cycle.
T
I
= integer multiple of T
BASE_IO
calculation: T
I
= 2 ∙ 125 µs = 250 µs
When T
I
= 0: T
I
= T
DP
T
I
2
T
I_MIN
= 1 Min. T
I
calculation: T
I_MIN
= 1 ∙ T
BASE_IO
= 125 µs
T
I_MIN
corresponds to the largest current controller cycle
(p0115[0]) of a drive object (servo/vector) in the drive unit.