WAGO-I/O-SYSTEM 750
MODBUS – CODESYS 2 283
750-8207 PFC200 CS 2ETH RS 3G
Manual
Draft version 1.2.1 from 2017-09-13, valid from FW Version 02.06.20(09)
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10.4 Data Exchange
MODBUS data exchange is performed in cycles or acyclically using MODBUS
services. The type and number of usable MODBUS services depends on the
area that is addressed. There are generally four MODBUS-relevant address
areas in the PFC200:
•
MODBUS input process image
(MODBUS Input) – is an area in the PIO
(PIO = Output Process Image), in which data from the PLC is provided in
cycles exclusively for MODBUS Read services.
•
MODBUS output process image
(MODBUS Output) – is an area in the PII
(PII = Input Process Image), in which MODBUS Write services provide data
for cyclic reading by the PLC. MODBUS Read services are also acceptable
in this area.
•
MODBUS flag area
– is an area, in which both MODBUS Read and Write
services can be executed.
•
MODBUS register
– is an area, in which the WAGO-specific information
and configuration registers are contained. Only MODBUS register services
may be executed in this area.
