5
5.8
Motion Control with PROFIBUS–DP (from SW 3.1)
5-300
Siemens AG 2005 All Rights Reserved
SIMODRIVE 611 universal Description of Functions (FBU) – 04.05 Edition
5.8.3
Times in the equidistant DP cycle
The ”DP slave 611U” requires the following time information for equidi-
stant operation, clock cycles and signal processing instants:
Table 5-37
Time settings for ”DP slave 611U”
Name
Value
1)
Limit value
Description
T
BASE_DP
5DC
hex
1500
dec
:
–
Time base for T
DP
Calculation: T
BASE_DP
= 1500
T
Bit
= 125
µ
s
T
Bit
= 1/12
µ
s at 12 Mbaud
T
DP
8
T
DP
T
DP_MIN
DP cycle time
T
DP
= integer multiple
T
BASE_DP
Calculation: T
DP
= 8
T
BASE_DP
= 1 ms
T
DP_MIN
= 8
Minimum 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
BASE_IO
5DC
hex
1500
dec
:
–
Time base for T
I
, T
O
Calculation: T
BASE_IO
= 1500
T
Bit
= 125
µ
s
T
Bit
= 1/12
µ
s at 12 Mbaud
T
I
2
T
I_MIN
T
I
< T
DP
Time of actual value sensing
Is the time, where the position actual value is sensed
before the start of a DP cycle.
T
I
= integer multiple of T
BASE_IO
Calculation: T
I
= 2
125
µ
s = 250
µ
s
For T
I
= 0, the following is valid: T
I
T
DP
T
I_MIN
= 1
Minimum T
I
Calculation: T
I_MIN
= 1
T
BASE_IO
= 125
µ
s
T
O
4
T
DX
+ T
O_MIN
T
O
T
DP
Time of setpoint transfer
This is the time that the setpoints (speed setpoint) are
transferred to the closed–loop control after the start of
DP cycle.
T
O
= integer multiple of T
BASE_IO
Calculation: T
O
= 4
125
µ
s = 500
µ
s
For T
O
= 0, the following is valid: T
O
T
DP
T
O_MIN
= 1
Minimum time interval between T
O
and T
DX
T
O_MIN
= 1
T
BASE_IO
= 125
µ
s
General
information
5 Communications via PROFIBUS DP
08.99
