To communicate with a Mitsubishi FR-E720 series Variable Frequency Drive (VFD) using the Modbus RTU protocol, you would typically follow these steps:
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Determine Communication Parameters: Find out the communication parameters required by the FR-E720 VFD, including the baud rate, data bits, parity, and stop bits. These parameters need to match the settings of your Modbus master device (e.g., PLC, HMI).
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Physical Connection: Connect the RS-485 communication port of the FR-E720 VFD to the RS-485 port of your Modbus master device using an RS-485 cable. Ensure proper wiring, including connecting A (positive) and B (negative) signals correctly.
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Address Configuration: Each FR-E720 VFD connected to the Modbus network must have a unique Modbus address. Refer to the FR-E720 VFD user manual for instructions on setting the Modbus address.
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Modbus Function Codes: Understand the Modbus function codes supported by the FR-E720 VFD. These function codes determine the type of operation (e.g., read holding register, write single register) that can be performed on the VFD.
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PLC/HMI Configuration: Configure your Modbus master device (e.g., PLC, HMI) to communicate with the FR-E720 VFD using the appropriate Modbus RTU communication parameters and function codes. Set up the communication channels and define the addresses of the VFD parameters you want to read or write.
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Testing and Troubleshooting: Test the communication between your Modbus master device and the FR-E720 VFD. Verify that you can read and write VFD parameters as intended. If you encounter any issues, check the wiring, communication settings, and Modbus addressing for errors.
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Integration with Control System: Once communication is established successfully, integrate the FR-E720 VFD into your control system application. Use the Modbus communication capabilities to monitor and control the VFD parameters as required for your application.
set the parameters below
Pr117 : “1” (Slave.1)
Pr118 : “9600” (Baud rate)
Pr119 : “0” (8bit/Stop bit.1)
Pr120 : “2” (Even bit)
Pr121 : “9999”
Pr122 : “9999”
Pr123 : “9999”
Pr124 : “1”
Pr340 : “1”
Pr549 : “1”
Pr79 : “6” ( External Mode > Last Setting )
Running Frequency: 13 (Hex “D”)
Inverter status/control input: 8 (Hex “8”)
Output Frequency: 200 (Hex “C8”)
Output Current: 201 (Hex “C9”)
Output Voltage: 202 (Hex “CA”)
