> For the complete documentation index, see [llms.txt](https://docs.smart-stuff.nl/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping/abb-b21.md).

# ABB B21

### Defaults

* Modbus device id: `2`
* RS485: `9600 8N1`
* Function codes: `FC03`
* Data format: `uint32` and signed `int32`
* Unavailable values: `0`

### Measurement registers

| Register | Description          | Type     | Unit / encoding |
| -------- | -------------------- | -------- | --------------- |
| `0x5B00` | voltage\_l1          | `uint32` | V x10           |
| `0x5B02` | voltage\_l2          | `uint32` | V x10           |
| `0x5B04` | voltage\_l3          | `uint32` | V x10           |
| `0x5B0C` | current\_l1          | `uint32` | A x100          |
| `0x5B0E` | current\_l2          | `uint32` | A x100          |
| `0x5B10` | current\_l3          | `uint32` | A x100          |
| `0x5B14` | active\_power\_total | `int32`  | W x100          |
| `0x5B16` | active\_power\_l1    | `int32`  | W x100          |
| `0x5B18` | active\_power\_l2    | `int32`  | W x100          |
| `0x5B1A` | active\_power\_l3    | `int32`  | W x100          |

### Device info

| Register | Description      | Value               |
| -------- | ---------------- | ------------------- |
| 400      | device id        | current `DevID`     |
| 402      | serial config    | encoded serial mode |
| 404      | baudrate         | actual baudrate     |
| 406      | pre4 meter flag  | `0` or `1`          |
| 408      | firmware version | packed `MMmmpp`     |
| 410      | dongle name      | packed `P1M3`       |