Hardware manual

Chapter2 Connection to a PLC
2-240
12.6 MODBUS/TCP Server
12.6.1 Overview of the MODBUS/TCP Server Communication
12.6.1.1 Overview
The MODBUS/TCP Server communication performs that PC or PLC (refers to as a host device)
can read and write the MICRO/I communication devices via the Ethernet.
The read/write of a device is performed using the MODBUS/TCP protocol. Up to 4 host devices
can be connected to the MICRO/I at same time.
12.6.1.2 Operation of the Communication
The host device is capable of reading/writing to the MICRO/I communication devices. It is also
possible to read/write communication devices from the MICRO/I.
12.6.1.3 Read/Write from the Host Device
The host device is capable of reading/writing the data in the data memory at the any timing.
PC, PLC, or other host
devices
Conceptual Diagram of Communication
1234
5678
HG2F/3F/4F
C
ommun
i
cat
i
on
device
Write
Read
HR 400001 1
HR 400002 127
HR 400003 0
HR 400004 0
～
～
～
～
HR 465535 1234
HR 465546 5678
C 0 1
C 1 0
C 2 0
C 3 0
～
～
～
～
C 65535 1
C 65536 0
MODBUS/TCP communication is the open protocol.
For detail information, visit the website at http://www.modbus.org/.