Efficient Networks Siemens Sinamics S120 User Manual
Page 418
Communication PROFIBUS DP/PROFINET IO
10.2 Communication via PROFIBUS DP
Drive Functions
418
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
Name
Value
1)
Limit value
Description
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
Servo calculation: T
O
= 4 ∙ T
BASE_IO
= 500 µs
When T
O
= 0: T
O
≐ T
DP
Vector calculation: T
O
= 4 ∙ 1000 µs = 4000 µs
When T
O
= 0: T
O
≐ T
DP
T
O
corresponds to the largest speed controller cycle (p0115[1])
of a drive object (vector) in the drive unit.
T
O
4
T
O_MIN
= 1
Servo:
Minimum time distance between T
O
and T
DX
T
O_MIN
= 1 ∙ T
BASE_IO
= 125 µs
Vector:
Minimum time distance between T
O
and T
DX
T
O_MIN
= 1 ∙ T
n_reg
= 1000 µs
T
n_reg
corresponds to the largest speed controller cycle
(p0115[1]) of a drive object (vector) in the drive unit.
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 • T
BIT
= 300 µs
T
PLL_W
0
-
PLL window
(half the width of the GC synchronization window)
The following applies to the setting:
•
Small window --> minimization of synchronization
fluctuations on the drive
•
Large window --> higher tolerance of GC fluctuations
Calculation (assumption: T
PLL_W
= A hex ≐ 10 dez)
T
PLL_W
= 10 • TBIT = 0.833 µs
T
Bit
= 1/12 µs at 12 Mbps
T
PLL_D
0
-
PLL dead time
The PLL dead time can be used to compensate for different
data transfer times to the slaves (e.g. due to repeaters).
The slaves with faster transfer times are delayed by a
corresponding PLL dead time.
Calculation: T
PLL_D
= 0 ∙ T
BIT
= 0 µs
T
Bit
= 1/12 µs at 12 MBaud
GC
Global Control Telegram (Broadcast Telegram)
T
TH
Token hold time
This time is calculated by the engineering system.
Dx
Data_Exchange
This service is used to implement user data exchange between
master and slave 1 - n.