YOKOGAWA UTAdvanced Series, User Manual

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4-3
IM 05P07A01-01EN
Description of Ethernet Communication (Modbus/TCP) (for UT
Advanced with Ethernet Communication)
4
4.2 TCP/IP-based Communication
Modbus/TCP performs transactions by the procedure in the figure below on the TCP/IP
socket interface.
socket()
socket()
bind()
listen()
accept()
connect()
send()
send()
recv()
recv()
close()
close()
PC
Initial Startup
Connection open
Command
Response
Connection
break
Initial Startup
UT75A/UT55A/
UT35A/UP55A/
UP35A with
Ethernet
communication
Ethernet
Note
If there is no request for at least 60 seconds from the host computer after the connection is
established, the UT75A/UT55A/UT35A/UP55A/UP35A breaks the connection.
The maximum number of transactions for UT75A/UT55A/UT35A/UP55A/UP35A is "1".
When sending commands continuously, send the next command after confirming the
response from UT75A/UT55A/UT35A/UP55A/UP35A. (See the figure below.)
Host device
(PC)
Command
(PV readout)
Command
(PV readout)
Command
(PV readout)
Response
(PV)
Response
(PV)
UT55A