2  PARAMETER SETTINGS
2.3  Application Settings
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2
■Automatic Response System
This system differs from the other conversion method in that specification can only be made when the own station is the 
communication request destination station or communication relay receiving station.
Relay communications via other networks can be performed easily because the IP address and port number of the destination 
station are not required to be set.
Conversion processing of the automatic response system is as below.
 • When receiving the communication request message (command frame), the Ethernet-equipped module internally stores 
the send source network number, IP address, and UDP port number in the request message, as the station information. 
The response message (response) for the communication request message is returned to the destination IP address and 
UDP port number calculated from the stored network number and station number. Therefore, by receiving the other station 
access communication request message first, the communication destination stations can be maintained.
 • The maximum number of station information that can be set is 120. When more than 120 other station access 
communication request messages are received, the Ethernet-equipped module starts deleting from the oldest data to store 
the station information in the newly received message communication request message. However, it is ignored if the station 
information is the same as the station information already stored. (Information from the same station is not stored twice.)
RJ71
EN71
RJ71
EN71
RJ71
EN71
Ethernet
Ethernet
RJ71
EN71
CPU
module
Communication relay receiving station
Communication relay sending station
Communication request source station
Communication request destination station
The automatic response 
system can be set.
CPU
module
CPU
module
Communication
request message
Previous
station
Response
message
Next 
station
Communication 
relay receiving 
station
Communication relay station
Communication 
relay sending 
station