1. Overview
The Delta MS300 VFD supports Modbus RTU communication through its RS485 interface. Based on Delta's official technical manual, this article explains the Modbus register address mapping of the MS300 VFD in detail.
2. Modbus Communication Parameters
| Parameter No. | Parameter Name | Description |
|---|
| 09.00 | Communication address | Sets the slave address (1-254) |
| 09.01 | Communication baud rate | Sets the baud rate (9600/19200/38400/115200) |
| 09.02 | Communication protocol | Selects the Modbus RTU protocol |
| 09.04 | Data format | Data bits / parity / stop bits settings |
3. MS300 Modbus Register Mapping Table
3.1 Control Command Registers
| Modbus Address | Parameter No. | Description | Read/Write |
|---|
| 2000H | 00.00 | Frequency command | Read/Write |
| 2001H | - | Run command | Read/Write |
3.2 Monitoring Parameter Registers
| Modbus Address | Parameter No. | Description |
|---|
| 2100H | 05.00 | Output frequency |
| 2101H | 05.01 | Output current |
| 2102H | 05.02 | Output voltage |
| 2103H | 05.05 | DC bus voltage |
| 2104H | 05.06 | Motor speed |
4. Run Command Word Bit Definition
| Bit | Function | Description |
|---|
| 0 | Run/Stop | 1 = Run, 0 = Stop |
| 1 | Forward/Reverse | 1 = Reverse, 0 = Forward |
| 2 | Jog run | 1 = Jog |
| 7 | Fault reset | Resets the fault on the rising edge |
5. FAQ and Troubleshooting
- Check whether parameter 09.02 (communication protocol) is set to Modbus RTU
- Confirm that the slave address and baud rate match those of the master
- The frequency setpoint unit is 0.01 Hz, i.e. 50.00 Hz is written as 5000
- The run command word must be operated bit by bit
6. Summary
Core registers for Delta MS300 VFD Modbus communication:
- 2000H → Frequency command
- 2001H → Run command
- 2100H → Output frequency
- 2101H → Output current
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