Siemens SIMODRIVE 611 universal Function Manual page 294

5 Communications via PROFIBUS DP
5.8 Motion Control with PROFIBUS–DP (from SW 3.1)
DP cycle
Prerequisites and
features
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Every DP cycle starts with a Global Control Telegram (GC), which is
then followed, one after the other, with the data transfer with the indivi-
dual slaves (S1, S2, ...).
The GC telegram is a broadcast telegram, sent from the master, and
which is received simultaneously by all slaves.
The internal clock cycles of the "DP slave 611U" are synchronized to
the DP clock cycle using this GC telegram and the PLL used for the
optional PROFIBUS–DP3 module.
The clock–synchronous coupling has the following prerequisites and
features:
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Prerequisites for the DP slave (refer to Chapter 1.3.3)
– "SIMODRIVE 611 universal" control board from SW 3.1
– Optional PROFIBUS–DP3 module with ASIC DPC31 and PLL
(Order No.: 6SN1114–0NB01–0AA0)
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Prerequisites for the DP master
– "Motion Control with PROFIBUS–DP" function
– Using a DP interface in the DP master, which can realize clock–
cycle synchronous operation
– Data transfer rate: Can be set between 1.5 and 12 Mbaud
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Telegram data transfer between a DP master and slave in equidis-
tant cycles.
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Post synchronization of the slave clock cycles to the equidistant DP
cycle via the Global Control Telegram at the start of a DP cycle.
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The maximum permissible fluctuations when recognizing a Global
Control Telegram (Jitter) via the optional PROFIBUS DP module is
dependent on the data transfer rate as follows:
Data transfer rate
12 Mbaud
3 or 6 Mbaud
1.5 Mbaud
Clock–synchronous operation with the "DP slave 611U" is only guar-
anteed when the maximum permissible jitter is maintained.
When configuring the bus system, it should be ensured, that espe-
cially when, e.g. repeaters or optical bus components are used, the
maximum permissible jitter is not exceeded.
SIMODRIVE 611 universal Description of Functions (FBU) – 04.05 Edition
Max. permissible jitter
1.0 µs
0.9 µs
0.8 µs
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