To communicate with an FR-E700 series Mitsubishi VFD (Variable Frequency Drive) using the Modbus RTU protocol, you would typically need to follow these steps:

1. Communication Parameters: Determine the communication parameters required by the FR-E700 VFD, such as baud rate, data bits, parity, and stop bits. These parameters should match the settings configured in your Modbus master device (e.g., PLC, HMI).

2. Physical Connection: Connect the RS-485 communication port of the FR-E700 VFD to the RS-485 port of your Modbus master device using an appropriate RS-485 cable. Ensure proper wiring of the RS-485 cable, including the connections for A (positive) and B (negative) signals.

3. Address Configuration: Each FR-E700 VFD connected to the Modbus network must have a unique Modbus address. Refer to the FR-E700 VFD user manual for instructions on setting the Modbus address.

4. Modbus Function Codes: Familiarize yourself with the Modbus function codes supported by the FR-E700 VFD. These function codes determine the type of operation (e.g., read holding register, write single register) that can be performed on the VFD.

5. PLC/HMI Configuration: Configure your Modbus master device (e.g., PLC, HMI) to communicate with the FR-E700 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.

6. Testing and Troubleshooting: Test the communication between your Modbus master device and the FR-E700 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.

7. Integration with Control System: Once communication is established successfully, integrate the FR-E700 VFD into your control system application. Use the Modbus communication capabilities to monitor and control the VFD parameters as required for your application.

parameters:
Pr117: Slave Address = 1
Pr118: Baud rate = 3 (9600)
Pr119: Bit-length & Stop bit = 0 (8bit & 1)
Pr120: Parity check = 2 (Even)
Pr121: = 9999
Pr122: = 9999
Pr123: = 9999
Pr124: = 1
Pr340: = 1
Pr79: = 2 – External Mode ( Last Setting )

Modbus Registers Address
With the FR-E700 Series inverter controlled via Modbus-RTU, the Modbus address will be calculated as follows:

Starting register address (decimal) – 40001

Ex: Parameter clear Modbus Address = (40003 – 40001) = 2
Setting Frequency = 40014 – 40001 = 13 (dec) = D (hex)

Motor Control Address = 40009 – 40001 = 8 (dec) = 8 (hex)

Forward Run = 0000 0000 0000 0010 = 2
Reverse Run = 0000 0000 0000 0100 = 4
Stop command = 0000 0000 0000 0000 = 0
I read 3 main parameters feedback from the inverter:
Output Freequency = 40201 – 40001 = 200 (dec) = C8 (hex)
Output Current
Output Voltage