Communication Procedure - Mitsubishi Electric FR-A820-00046 Instruction Manual

Ethernet communication (FR-A800-E)

Communication procedure

● Using TCP/IP
The following is the communication procedure when executing SLMP communication with TCP/
IP. With TCP/IP, connections are established when communication is executed, and whether data
is received normally or not is checked to ensure reliability of data. However, the line load is high
as compared to UDP/IP.
The process is repeated as needed.
Fig. 5-384:
5 - 772
External device
Connection request
The external device issues a connection request
to the inverter. (Active open)
Sending a request message
Upon establishment of the connection, the
external device sends a request message to the
inverter.
Receiving the response message
The external device receives the response
message from the inverter and confirms the
operation result.
Closing the connection
The external device issues a close request to the
inverter and closes the communication.
Communication procedure when executing SLMP communication with TCP/IP
Inverter
Connecting operation
The inverter accepts the connection request
from the external device. (Passive open)
Execution of the operation
According to the request message sent from the
external device, the inverter executes a reading,
writing, or other operation.
Returning a response message
Upon completion of the operation, the inverter
sends a response message to the external
device.
Closing the connection
The inverter accepts the close request from the
external device and closes the communication.
Parameters
I003116E