Communications
configuring
System- and communication configuring D7-SYS - SIMADYN D
3-141
Edition 12.2003
3.13.2
Data transfer technique
Data transfer is realized in the half-duplex mode via an RS485 interface
(2-conductor cable). The master addresses all of the slaves, one after
another, with a telegram. The addressed slaves transmit a telegram back
to the master. In accordance with the master-slave procedure, when the
slave receives a telegram, it must first transmit a telegram back to the
master before the master re-addresses this slave.
The sequence of the addressed slaves can be specified by entering the
station address in a circulating list (refer to the central coupling block
@CSU). If several slaves must be addressed in a faster cycle (scan) than
the others, then their station address can be configured a multiple
number of times in the circulating list.
The scan time isn’t defined due to the inconsistent telegram delay- and
processing times.
0
0
1
1
0
0
t0
t1
t2
t3
t4
t5
t6
Cycle time
t0: Telegram delay time, master-slave0
t1: Response delay time, slave0
t2: Telegram delay time, slave0-master
t3: Processing time, master
t4: Telegram delay time master-slave1
t5: Response delay time, slave1
t6: Telegram delay time slave1-master
...
Fig. 3-48
Definition of the cycle time
3.13.3
Transferred net data
On the receive- as well as on the transmit side, up to 252 bytes of net
data can be transferred. The net data length can be configured and is
dependent on the particular application.
3.13.4 Configuring
3.13.4.1
Central coupling block @CSU
An @CSU central coupling block has to be configured to initialize and
monitor the coupling. The central block only initializes the coupling during
cyclic operation; the coupling remains inhibited before cyclic operation.
Mode of operation
General
Initialization and
monitoring
