CHINT · Energy meter
DDSU666 single-phase smart meter (iStoragE meter) Modbus register map
Default configuration
- Protocol
- RS485
- Port
- 502
- Unit ID
- 3
- Addressing
- 0-based
- Byte order
- Big endian
- Word order
- High word first
- Baud rate
- 9600
- Parity
- None
- Data bits
- 8
- Stop bits
- 1
This device has an RS-485 interface. Reach it through a Modbus RTU-to-TCP gateway, configured with the factory serial settings above.
Register map
| Address | Count | Name | Type | Unit | Scale | Access |
|---|---|---|---|---|---|---|
| 8192 | 2 | Voltage Secondary-side voltage (2000H). The manual prints no unit for this register. | Float32 | - | 1 | R |
| 8194 | 2 | Current Secondary-side current (2002H). The manual prints no unit for this register. | Float32 | - | 1 | R |
| 8196 | 2 | Active power | Float32 | kW | 1 | R |
| 8198 | 2 | Reactive power | Float32 | kvar | 1 | R |
| 8202 | 2 | Power factor | Float32 | - | 1 | R |
| 8206 | 2 | Frequency | Float32 | Hz | 1 | R |
| 16384 | 2 | Forward active energy Active (import) energy (4000H). The manual prints no unit for this register. | Float32 | - | 1 | R |
| 16394 | 2 | Reverse active energy Reverse (export) energy (400AH). The manual prints no unit for this register. | Float32 | - | 1 | R |
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Related guides
Notes
Source: CHINT 'DDSU666 Single-phase Smart Meter User Manual', document ZTY0.464.1413, served by CHINT Italy at chint.it (iStoragE document area): https://chint.it/wp-content/uploads/product-docs/iStoragE/Manuali/iStoragE%20Meter%20DDSU666%20User%20Manual%20EN.pdf. Factory defaults from section 4.2: default baud rate 9600 bps with 'check bit and stop bit to be n.1' (no parity, 1 stop bit) and default communication address 03; the meter display menu in section 3 shows the same frame (8 data bits, None parity, 1 stop bit). Addressing: the register map prints hexadecimal register addresses (2000H, 4000H, ...) and Appendix A's worked frames put those hex numbers in the start-address field unchanged, so they are zero-based wire addresses, stored here as decimal (2000H = 8192 over to 400AH = 16394, 0002H = 2 over to 000CH = 12). All measured values are single-precision IEEE-754 floating point in two registers, so no scale factor is applied. The manual prints no word-order example for those pairs, so the seed keeps the Modbus standard order with the high word in the lower register (HighFirst); if a unit returns nonsense, try LowFirst. Document contradiction recorded rather than hidden: Appendix A.1 describes an 11-bit character frame ('1 start bit, 8 data bits and 2 stop bits') while section 4.2 and the display menu state the factory setting 'n.1' (1 stop bit); this seed follows the explicit factory-setting sentence and the menu, and the reader should confirm the stop-bit setting on their own unit. Deliberate omissions: the RESERVED rows (0000H-0001H, 0003H-0004H, 0007H-000AH, 000DH-0010H, 2008H, 200CH, 2010H), the version/firmware value in 0000H whose description the manual prints against the RESERVED row, and polarity/tariff rows that the manual does not tabulate. This is the single-phase DDSU666; the library's chint-dtsu666 seed covers the three-phase DTSU666/DSSU666, which is a different product with a different map.