Precautions For Using Web Function - Mitsubishi Electric MELSEC-Q Series User Manual

2.2

Precautions for Using Web Function

(1) Precautions for configuring a system
(a) It is necessary to take sufficient security measures for connection to the Internet.
Consult with a network installer, an Internet service provider, and a network administrator (person in charge of
network planning and IP address management).
Mitsubishi Electric Corporation will not take any responsibility for any system problems that may occur while
connecting to the Internet.
(b) If a firewall function is installed in the network, set it so that the HTTP protocol can
pass the firewall function.
(c) When accessing multiple Ethernet modules via one Web server, the next process
may not be executed during the time from the request start through until the
response is returned.
If no response is received due to a communication line fault, the next processing may be delayed until a
timeout occurs on the Web server.
Ex.
Accessing 2 Ethernet modules using one Web server
Web browser 1)
Web browser 2)
• Access from Web browser 1) to Ethernet module 1)
• Access from Web browser 2) to Ethernet module 2)
The line fault between the Web server and Ethernet module 1) disables the response from Ethernet module 1)
to the Web server. This brings the Web server into the wait status and the access request from Web browser 2)
to Ethernet module 2) has to wait at the Web server.
Because no response is received
from Ethernet module 1), the next
request cannot be handled.
Web server
Internet
CHAPTER 2 SYSTEM CONFIGURATIONS
Ethernet module 1)
Line fault
Intranet
Ethernet module 2)
Response to
Web server
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