Communications Using An Auto-Open Udp Port; Application - Mitsubishi Electric MELSEC-L SERIES Basic User Manual

14.2

Communications Using an Auto-open UDP Port

This section describes communications using the auto-open UDP port.
14.2.1

Application

The auto-open UDP port is a UDP/IP port that automatically opens and closes at the following timing. Using this port
makes the E71 ready for communications upon completion of an initial process, thus enabling communications without
using any programs regardless of the open status of connection numbers 1 to 16.
(1) Open and close timing
The port automatically opens according to the registered parameter settings upon completion of the initial
process of the E71. In addition, it automatically closes when the E71-connected station is powered off or reset.
● The E71 enables communications using an auto-open UDP port after the initial process is normally completed, and the
E71 on the own station waits for communication requests to itself (auto open).
● The E71 accepts requests from anywhere as long as they are addressed to the E71 itself.
● When a communication request is accepted from the connected device, the corresponding port number is occupied until
the process is completed. Even if the next communication request is accepted during this time, the communication
process will be waited.
● To change the auto-open UDP port number, a reinitialization process is required. (
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Page 315, Appendix 4.2)