Communications configuring
3-14
System- and communication configuring D7-SYS - SIMADYN D
Edition 12.2003
Transmitter
KVL
NDP1
NDP1
....
Receiver 1
Receiver 2
Receiver n
KVL = channel
NDP =net data buffer
Fig. 3-4
Data transfer in the "Multiple" mode
The "Image" data transfer mode” is used for the FM 458-1 DP to
communicate via the PROFIBUS DP interface,
•
if all of the receivers, which are configured in a task, should be
provided with data that come from the same DP cycle,
•
if all transmitters, which are configured in the same task, wish to send
their data to the DP slaves in the same DP cycle.
To do this, transmitter and receiver FBs synchronize themselves within a
task in order to supply consistent data. They form a so-called
“
consistency group
”. All receiver FBs, associated with such a
consistency group, fetch their net (useful) data from a common
alternating buffer and all of the transmitter FBs deposit their data in such
a buffer.
"Image" is an overwriting data exchange (refer to refresh). There are two
net (useful) data buffers which are used for data exchange. They are
used as alternating buffer system.
This data transfer mode is only permitted for the PROFIBUS DP interface
of the FM458-1 DP application module.
"Image" data
transfer mode
