Process Data Of The Modbus Server; Accessing The Process Image Via Modbus Functions; Table 44: Modbus Function Codes - WAGO -I/O-IPC-C6 Manual

92 MODBUS/TCP
10.1

Process Data of the MODBUS Server

The first analog output or input or the digital (if there is no analog one) is reached
via the word services of the MODBUS server.
A particularity of access via MODBUS is that with the "digital" MODBUS
services on the I/O-IPC address 0, you always access the first digital output or
input of the internal data bus process image, although digital and analog process
data of the I/O-IPC and the I/O modules are combined into one process image.
For information about the length of the process data, please see section "Process
Data Architecture for MODBUS/TCP."
Activating "Control Mode" in WAGO-IO-CHECK!
Using WAGO-IO-CHECK, you can overwrite parameters and process data in
"Control Mode" regardless of whether the fieldbus or PLC functionalities are
enabled or disabled. By doing so, machine components may be placed in a
dangerous state and personnel and machines may be at risk.
Before changing parameters and process data, ensure that the machine
components are in a safe and defined state and switch off the higher-level
controller. Also ensure before start-up that no personnel remain in the danger area
of the machine components.
10.2 Accessing the Process Image via MODBUS
Functions
The following table describes the MODBUS function codes with which you can
access the address ranges of the process image for the inputs and outputs
connected to the internal data bus and the fieldbus:

Table 44: MODBUS Function Codes

FC Name
FC1 Read coils
FC2 Read inputs discrete
FC3 Read holding registers
FC4 Read input registers
FC5 Write coil
FC6 Write single register
FC15 Force multiple coils
FC16 Write multiple registers
FC23 Read/write multiple registers
758-874/000-131 WAGO-I/O-IPC-C6
Description
Several digital output values are read out
Several digital input values are read
Several analog output values are read
Several analog input values are read
A single digital output value is written
A single analog output value is written
Several digital output values are written
Several analog output values are written
Read and write operation on analog input and output
values
WAGO-I/O-SYSTEM 750
Manual
Version 1.0.0