12.2010 Communication / SIMOLINK
Siemens AG 6SE7087-6QX70 (Version AM)
SIMOVERT MASTERDRIVES Compendium Motion Control 8.3-3
♦ MASTERDRIVES MC only:
Synchronization of the nodes is effected through a SYNC telegram
which is generated by a node with a special function, the dispatcher
function, and is received simultaneously by all other nodes. The
SYNC telegram is generated absolutely time-equidistantly and jitter-
free. The time between two SYNC telegrams is the bus cycle time of
SIMOLINK and, at the same time, it corresponds to the common
clock time for synchronization of all connected nodes.
♦ Data transfer between nodes is effected strictly cyclically in the bus
cycle clock time. This means that all data written or read by the
nodes is transferred between two SYNC telegrams. Upon receipt of
the SYNC telegram, the previously received data in every
MASTERDRIVES MC/VC unit is passed on to the control system of
the converter as being the currently applicable data. This ensures
that the latest applicable data is available to all nodes on the bus at
the same time.
Bus cycle = system clock Bus cycle = system clock
t
SYNC Pause SYNC PausePause
SYNC telegram SYNC telegram
Telegrams for
data transfer
of nodes
Telegrams for
data transfer
of nodes
Fig. 8.3-2 SIMOLINK telegram traffic
♦ The transfer rate is a fixed 11 MBit/s
♦ A 32 bit word can be transferred in each telegram. The total length
of each telegram is 70 bit, including the 32 bit net information. Thus,
at a transfer rate of 11 Mbit/sec, a telegram has a transfer time of
s 366. μ
.
♦ SIMOLINK has a very high data throughput. This means that all the
telegrams are sent without an interval directly one after the other.
For example, with a selected bus cycle time of 1 ms, 155 telegrams
with data contents (value of 32 bit per telegram) can be transferred
via SIMOLINK.
♦ The functionality of the SIMOLINK application defines the
assignment of telegrams to nodes. There are two possible
applications:
• the peer-to-peer functionality and
• the master/slave functionality.
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