To communicate with a Delta MS300 Variable Frequency Drive (VFD) using the Modbus RTU protocol via Modbus Poll software, follow these steps:

1. Set Up Communication Parameters:

   • Determine the communication parameters required by the MS300 VFD, such as baud rate, data bits, parity, and stop bits. These parameters need to match the settings configured in Modbus Poll.
   • Open Modbus Poll and configure the communication settings in the "Connection" tab to match those of the MS300 VFD.
   • DELTA MS300 VFD Communication Setting

     In addition to the parameters of the inverter installed according to the motor (frequency, voltage, current), we need to set the communication parameters as follows:

     P00.20 = 1 (Modbus-RTU Control Frequency)

     P00.21 = 2 (Modbus-RTU Control Motor)

     P09.00 = 1 (Address Slave = 1)

     P09.01 = 9.6 (9600bps)

     P09.02 = 0

     P09.03 = 1.0 (Time Detect Err = 1.0s)

     P09.04 = 14 (Modbus-RTU Slection 8bit / stop bit = 1/ Even)

2. Define the Modbus Slave Device:

   • In Modbus Poll, define a new Modbus slave device representing the Delta MS300 VFD. Enter the appropriate Modbus address assigned to the VFD.

3. Select Function Codes:

   • Determine which Modbus function codes you need to use to read or write data from/to the MS300 VFD. These function codes may include reading holding registers (e.g., for frequency reference, status, or operating parameters) or writing to holding registers (e.g., for setting frequency commands or control commands).
   • Configure Modbus Poll to use the appropriate function codes for the desired operations.

4. Test Communication:

   • Once the communication parameters and function codes are set up in Modbus Poll, attempt to establish communication with the Delta MS300 VFD.
   • Verify that you can read data from the VFD (e.g., status, frequency) and write data to it (e.g., frequency commands).
   • If communication is successful, you should be able to monitor and control the MS300 VFD parameters using Modbus Poll.

5. Troubleshooting:

   • If you encounter any issues with communication, double-check the communication parameters (baud rate, data bits, parity, stop bits), Modbus address, and function codes.
   • Ensure that the physical connection between the computer running Modbus Poll and the MS300 VFD is properly established, and the RS-485 wiring is correct.

6. Integration with Control System:

   • Once communication is established and tested successfully, integrate the MS300 VFD into your control system application.
   • Use Modbus Poll or other software to monitor and control the VFD parameters as required for your application.

By following these steps, you should be able to communicate with a Delta MS300 VFD using the Modbus RTU protocol via Modbus Poll software. Always refer to the user manuals and documentation provided by Delta and Modbus Poll for detailed instructions and specifications specific to your setup.