Communication Structure - Mitsubishi Electric MELSEC-L SERIES Basic User Manual

9.2

Communication Structure

When a connected device sends a message to an E71 in the MC protocol message format, the E71 performs the
process according to the message. During communications, a CPU module including the E71 operates as a server,
and the connected device (a personal computer or other terminals) operates as a client. Based on the command
message received from the client, the server (the E71) automatically sends an appropriate response message.
Ethernet
The frames that can be used with an E71 are as follows.
• 4E frame
• QnA-compatible 3E frame
• A-compatible 1E frame
86
Server
E71
Command message
Header
Subheader
Header
Application data
Text (command)
Response message
Application data
Subheader Text (command)
Client
Connected device