Siemens SIMOREG DC Master 6RA7028-6DS22 Operating Instructions Manual page 177

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A separate address is assigned to each active bus node; the dispatcher is always assigned node
address 0.
A maximum of 8 telegrams can be transferred per active node. The number of telegrams used per
node is a parameterizable quantity.
Telegrams are identified by the node address and distinguished by their channel number of
between 0 and 7, with 2 data words transferred as user data in each telegram. The first channel
number starts with 0 and is counted in ascending sequence.
The assignment between connector values to be transferred and individual telegrams and channels
is also parameterized (see Section 8, Sheet Z122).
Apart from these data, a SIMOLINK master can also send special telegrams with application-
specific data (addresses 201 to 204 and channel number 0). An SLB as dispatcher does not
support these special telegrams.
If a transceiver stops receiving telegrams due to an interruption, it automatically transmits special
telegram "Time Out".
The transmission rate is 11 Mbits/s. The data telegrams are transmitted in direct succession,
followed by a SYNC telegram and a pause telegram, within one bus cycle. Transferring the data
telegrams without pauses ensures a higher data throughput. At a data transmission rate of 11
Mbit/s, the transmission time for one telegram is 6.36µs.
The assignment of telegrams to nodes is determined by the type of SIMOLINK application, i.e.
peer-to-peer functionality or master-slave functionality.
When an SLB is configured as the dispatcher, only the peer-to-peer functionality is available.
Peer-to-peer functionality
In this mode, there is no defined logical master for distributing information. The drives have equal
status in logical terms and exchange data with one another via the ring bus. One node (SLB)
specifies the bus cycle in its dispatcher role to keep the transmission alive. All nodes receive and/or
send user data. Dispatcher and transceivers can read any telegram, but may only write information
in the telegrams specifically assigned to them (node address = address in telegram).
Master-slave functionality
A logical master (e.g. SIMATIC) supplies all nodes with information on the one hand and, on the
other, specifies the bus clock cycle (dispatcher function). All other nodes behave as described
above under peer-to-peer functionality, i.e. they receive and/or send user data, but are only
permitted to read or write telegrams containing their address.
In contrast to peer-to-peer functionality, the restrictions described above (no gaps in address
sequence, uniform number of used channels, no special data) do not apply. The master has its own
8 channels for transferring data, but can also use telegrams with the address and channel numbers
of the transceivers for its data transmissions.
SIEMENS AG 6RX1700-0AD76
SIMOREG DC Master Operating Instructions
Telegram
Word0
Application Flags
Channel number
Node address
Bus cycle
. . .
Data telegrams
Word1
SYNC Break
Start-Up
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