Siemens SINAMICS S120 - Page 142

Communication via PROFIBUS
Motion control with PROFIBUS
4-142
E Siemens AG, 2004. All rights reserved
SINAMICS S120 Installation and Start-Up Manual, 12/04 Edition
Table 4-18 Time settings and meanings, continued
Name DescriptionLimit valueValue
1)
T
DP_MIN
= 8 Minimum DP cycle time
Calculation: T
DP_MIN
= 8 S T
BASE_DP
= 1 ms
T
MAPC
1 n S 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 S T
DP
= 1 ms
T
SAPC
Slave application cycle time
T
BASE_IO
5DC hex

1500 dec
– Time base for T
I
, T
O
Calculation: T
BASE_IO
= 1500 S T
Bit
= 125 µs
T
Bit
= 1/12 µs at 12 Mbaud
T
I
2 T
I_MIN
 T
I
< T
DP
Time of actual-value sensing
This is the time at which the actual position value is cap-
tured before the start of each cycle.
T
I
= integer multiple of T
BASE_IO
Calculation: T
I
= 2 S 125 µs = 250 µs
For T
I
= 0: T
I
= T
DP
T
I_MIN
= 1 Minimum T
I
Calculation: T
I_MIN
= 1 S T
BASE_IO
= 125 µs
T
O
4 T
DX
+ T
O_MIN
 T
O
 T
DP
Time of setpoint transfer
This is the time at which the transferred setpoints (speed
setpoint) are accepted by the closed-loop control system
after the start of the cycle.
T
O
= integer multiple of T
BASE_IO
Calculation: T
O
= 4 S 125 µs = 500 µs
For T
O
= 0: T
O
 T
DP
T
O_MIN
= 1 Minimum time interval between T
O
and T
DX
T
O_MIN
= 1 S T
BASE_IO
= 125 µs
T
DX
E10 hex

3600 dec
T
DX
< T
DP
Data exchange time
This is the time required within one cycle for transferring
process data to all available slaves.
T
DX
= integer multiple of T
Bit
T
Bit
= 1/12 µs at 12 Mbaud
Calculation: T
DX
= 3600 S T
BIT
= 300 µs