WAGO I/O SYSTEM 750 XTR
Modbus – CODESYS 2 293
750-8202/040-001 PFC200 2ETH RS TELE XTR
Manual
Version 1.2.0, valid from FW Version 03.01.07(13)
9.4.1
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 98: 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.