Figure 82: Example Scada Software With Modbus Driver; Table 470: Modbus Table And Function Codes - WAGO -I/O-SYSTEM 750 Manual

400 Application Examples
Example of the MODBUS Addressing
In the case of SCADA Software Lookout from National Instruments the MODBUS
function codes are used with a 6 digit coding, whereby the first digit represents
the MODBUS table (0, 1, 3 or 4) and implicit the function code (see following
table):

Table 470: MODBUS Table and Function Codes

MODBUS table
0
1
3
4
The following five digits specify the channel number (beginning with 1) of the
consecutively numbered digital or analog input and/or output channels.
Examples:
• Reading/writing the first digital input:
• Reading/writing the second analog input:
Application Example:
Thus, the digital input channel 2 of the above node "Measuring data" can be read
out with the input: "Measuring data. 0 0000 2".

Figure 82: Example SCADA Software with MODBUS Driver

Additional Information
Please refer to the respective SCADA product manual for a detailed description
of the particular software operation.
Manual
1.5.0
750-882 Media Redundancy ETHERNET Controller
MODBUS function code
FC1 or
FC15
FC2
FC4 or
FC 16
FC3
Adapt the addressing of the SCADA
software to the process image of the node
ETHERNET TCP/IP
MODBUS protocol
ETHERNET
adapter
Reading of input bits or
writing of several output bits
Reading of several input bits
Reading of several input registers or
writing of several output registers
Reading of several input registers
Exemplary node "Measuring data"
Hub
WAGO-I/O-SYSTEM 750
i.e. 0 0000 1
i.e. 3 0000 2