Communications
configuring
System- and communication configuring D7-SYS - SIMADYN D
3-143
Edition 12.2003
3.13.4.3 Telegram
types
The "Drive" telegram type should be used for communications to
variable-speed drives. Drive telegrams are exclusively transmitted as
standard telegrams in accordance with the drive profile (refer to /1/).
The "OP2" telegram type should be used for establishing
communications to operator control devices. OP2 telegrams are
exclusively transmitted as special telegrams (refer to /1/).
Station address "99" should be configured for communications using
broadcast telegram. Broadcast telegrams are only transmitted as special
telegrams (refer to /1/). Broadcast telegrams cannot be transmitted to
drives ("drive" telegram type)!
The master can request a mirror telegram from a slave. To realize this,
the master transmits a telegram to the slave. This telegram differs from
the standard telegram only by the fact that one bit of the address byte is
set. The slave transmits this telegram unchanged back to the master
(mirrored). This mirror telegram can be used to check data transfer
between master and slave. Mirror telegrams are transmitted, dependent
on the configured telegram type, either as standard telegram in
accordance with the device profile ("drive" telegram type) or as special
telegram ("OP2" telegram type) (refer to /1/).
3.13.5
Mode of operation
The USS master coupling cyclically transmits data, whereby all of the
slave nodes are addressed one after the other. In this case, it is
unimportant whether new transmit data were made available by the
blocks or not. If no new data was made available, then the data which
were last transmitted, are again transferred.
The USS master coupling only identifies a valid receive telegram, if the
number of received net data is the same as the configured number of
receive data.
The sequence of the slaves which are addressed can be specified by
appropriately entering the station address in a circulating list (also refer to
the central coupling block @CSU). If several slaves are to be addressed
in a faster cycle than others, then their station address can be configured
a multiple number of times in the circulating list.
If a circulating list is not configured, all of the slaves are addressed
according to their station address in an increasing sequence.
In the broadcast mode (station address=99), the master transmits a
telegram to all of the slaves connected to the bus. The slaves do not
respond to a broadcast telegram. The broadcast telegram is processed at
the end of each bus circulation (all slaves are addressed once). In this
case, a maximum of two broadcast telegrams are transmitted. If the
maximum of 16 possible broadcast tasks are available, these are
transmitted after 8 bus cycle. The USS master coupling ensures that a
Drive telegram
OP2 telegrams
Broadcast
telegrams
Mirror telegrams
Transmit
Receiving
Circulating list
Broadcast
