BACnet/IP Controller 750-830
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Data Exchange
WAGO-I/O-SYSTEM 750
BACnet/IP Controller
3.1.6.4 Data Exchange between PLC Function (CPU) and Bus Modules
The PLC function (CPU) of the PFC uses absolute addresses to access the bus
module data directly.
The PFC uses absolute addresses to reference the input data. The data can then
be processed internally in the controller using the IEC 61131-3 program. Flags
are stored in a remanent memory area in this process. The results of linking
can then be written directly to the output data employing absolute addressing.
%IW0
%QW0
%QW255
%IW255
%IW512
%IW1275
%QW512
%QW1275
PII = Process Input
Image
PIO = Process Output
Image
Inputs
Outputs
I/O modules
750-4xx....6xx
PII
PIO
PLC functionality (CPU)
Inputs
Outputs
Programmable Fieldbus Controller
Fig. 3-10: Data exchange between PLC function (CPU) of the PFC and the bus modules
g015043d
3.1.6.5 Data Exchange Between Master and PLC Function (CPU)
The fieldbus master and the PLC function (CPU) of the PFC have different
perspectives on data.
Variable data generated by the master is routed as input variables to the PFC,
where it is further processed.
Data created in the PFC is transmitted via the fieldbus to the master as output
variables.
In the PFC, access to the MODBUS/TCP PFC variable data is possible start-
ing from word address 256 to 511 (double-word address 128-255, byte address
512-1023), while access to the PFC variable data is possible starting from a
word address of 1276 to 1531 (double-word address 638-765, byte address
2552-3063).
