Process Image; Figure 106: Modbus Process Image - WAGO 750-8207 Manual

284 MODBUS – CODESYS 2
10.4.1

Process Image

The main data interfaces between the PLC and the MODBUS slave are the local
MODBUS process images in the PLC address area based on IEC 61131. The
MODBUS input process image (MODBUS Input) is in the PIO and the MODBUS
output process image (MODBUS Output) in the PII. Data memory blocks of 2 kB
(1000 registers/word) are available for each local MODBUS input and output
process image. The first 768 bytes of each of these data blocks are also provided
for executing bit services.

Figure 106: MODBUS Process Image

As no direct access to the I/O modules is provided by the fieldbus, data can be
exchanged via this interface between the PLC and MODBUS for processing in
the control system (PLC). Using this data in the individual I/O modules connected
to the PLC can then be performed by the application.
Manual
Draft version 1.2.1 from 2017-09-13, valid from FW Version 02.06.20(09)
WAGO-I/O-SYSTEM 750
750-8207 PFC200 CS 2ETH RS 3G