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Programmable Field Bus Controller 750-833
Process Image
3.4.3 Process Data Structure for PROFIBUS-DP
With some I/O modules, the structure of the process data is field bus specific.
Depending on how the coupler is parameterized, the status bytes (S), control
bytes (C) and data bytes (D0...Dn) of the byte or word orientated modules are
transmitted via PROFIBUS in Motorola or Intel format.
More Information
You can find the field bus specific process data structure for all I/O Modules
of WAGO-I/O-SYSTEM 750 and 753 in chapter 5.2, "Design of the Process
Data for PROFIBUS-DP".
3.4.4 Data Exchange
For data exchange, the controller is equipped with three interfaces:
• The interface to field bus (-master),
• The PLC functionality of the PFC (CPU) and
• The interface to the bus modules
Data exchange takes place between the field bus master and the bus modules,
between the PLC functionality of the PFC (CPU) and the bus modules as well
as between the field bus master and the PLC functionality of the PFC (CPU).
3.4.5 Memory Areas
The controller uses a memory space of 256 words (word 0 ... 255) for the
physical input and output data. The controller is assigned an additional
memory space for mapping the PFC variables defined according to
IEC 61131-3. This extended memory space (word 256 ... 511 each) is used to
map the PFC variables behind the physical process image. The division of the
memory spaces and the access of the PLC functionality (CPU) to the process
data is identical with all WAGO field bus controllers. Access is via an
application related IEC 61131-3 program and independent on the field bus
system.
Access from the field bus side is field bus specific.
WAGO-I/O-SYSTEM 750
Bus System
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