Technical data

Fieldbus Communication • 229
MODBUS Functions
WAGO-I/O-SYSTEM 750
BACnet/IP Controller
4.3.4 MODBUS Register Mapping
The following tables display the MODBUS addressing and the corresponding
IEC61131 addressing for the process image, the PFC variables, the NOVRAM
data, and the internal variables is represented.
Via the register services the states of the complex and digital I/O modules can
be determined or changed.
Register (Word) Access Reading (with FC3, FC4 and FC23):
MODBUS-Address IEC61131
[
dec
]
[
hex
]
Address
Memory Range
0
... 255
0x0000
... 0x00FF
%IW0
... %IW255
Physical Input Area (1)
First 256 Words of physical input data
256
... 511
0x0100
... 0x01FF
%QW256
... %QW511
PFC-OUT-Area
Volatile PFC Output variables
512
... 767
0x0200
... 0x02FF
%QW0
... %QW255
Physical Output Area (1)
First 256 Words of physical output data
768
... 1023
0x0300
... 0x03FF
%IW256
... %IW511
PFC-IN-Area
Volatile PFC Input variables
1024
... 4095
0x0400
... 0x0FFF
- MODBUS Exception:
“Illegal data address”
4096
... 12287
0x1000
... 0x2FFF
- Configuration Register (see following Chapter
4.3.5.3 Configuration Functions)
12288
... 24575
0x3000
... 0x5FFF
%MW0
... %MW12287
NOVRAM
8kB retain memory (max. 24kB)
24576
... 25340
0x6000
... 0x62FC
%IW512
... %IW1275
Physical Input Area (2)
Additional 764 Words physical input data
25341
... 28671
0x62FD
... 0x6FFF
- MODBUS Exception: “
Illegal data address”
28672
... 29436
0x7000
... 0x72FC
%QW512
... %QW1275
Physical Output Area (2)
Additional 764 Words physical output data
29437
... 65535
0x72FD
... 0xFFFF
- MODBUS Exception: “
Illegal data address”
Register (Word) Access Writing (with FC6, FC16, FC22 and FC23):
MODBUS-Address IEC61131
[
dec
]
[
hex
]
Address
Memory Range
0
... 255
0x0000
... 0x00FF
%QW0
... %QW255
Physical Output Area (1)
First 256 Words of physical output data
256
... 511
0x0100
... 0x01FF
%IW256
... %IW511
PFC-IN-Area
Volatile PFC Input variables
512
... 767
0x0200
... 0x02FF
%QW0
... %QW255
Physical Output Area (1)
First 256 Words of physical output data
768
... 1023
0x0300
... 0x03FF
%IW256
... %IW511
PFC-IN-Area
Volatile PFC Input variables
1024
... 4095
0x0400
... 0x0FFF
- MODBUS Exception:
“Illegal data address”
4096
... 12287
0x1000
... 0x2FFF
- Configuration Register (see following Chapter
4.3.5.3 Configuration Functions)