Modbus Map
These Modbus maps are for your reference. The modbus service runs on port 502.
Important note: The Ampt ModBus register map uses big endian values.
SunSpec Registers
| Start Offset | Size | Name | Type | R/W | Description |
| 1 | 2 | SID | uint32 | R | A well-known value 0x53756e53, uniquely identifies this as a SunSpec Modbus Map |
| 3 | 1 | ID | uint16 | R | A well-known value 1, uniquely identifies this as a SunSpec Common Model |
| 4 | 1 | L | uint16 | R | Well-known # of 16-bit registers to follow: 66 |
| 5 | 16 | Manufacturer | string | R | A well-known value registered with SunSpec for compliance: "Ampt" |
| 21 | 16 | Model | string | R | Manufacturer specific value "Communication Unit" |
| 37 | 8 | Reserved | - | - | |
| 45 | 8 | Version | string | R | Software Version |
| 53 | 16 | Serial Number | string | R | Manufacturer specific value |
| 69 | 1 | Device Address | int16 | R/W | Modbus Device ID |
| 70 | 1 | Reserved | - | - | |
| 71 | 1 | ID | uint16 | R | Ampt SunSpec Vendor Code 64050 |
| 72 | 1 | L | uint16 | R | Variable number of 16-bit registers to follow: 12 + N*16 |
| 73 | 1 | DCA_SF | int16 | R | Current scale factor |
| 74 | 1 | DCV_SF | int16 | R | Voltage scale factor |
| 75 | 1 | Reserved | - | - | |
| 76 | 1 | DCkWh_SF | int16 | R | Energy Scale Factor |
| 77 | 1 | Reserved | - | - | |
| 78 | 1 | N | uint16 | R | Number of strings |
| 79 | 6 | Reserved | - | - | |
| 1 | |||||
| 85 | 1 | String ID | int16 | R | The string number |
| 86 | 2 | Reserved | - | - | |
| 88 | 2 | String data timestamp | uint32 | R | The UTC timestamp of the measurements |
| 90 | 1 | OutDCA | int16 | R | String output current in mA |
| 91 | 2 | OutDCV | uint32 | R | String output voltage in mV |
| 93 | 2 | In1DCV | uint32 | R | String input 1 voltage in mV |
| 95 | 2 | In2DCV | uint32 | R | String input 2 voltage in mV |
| 97 | 2 | DCWh | uint32 | R | Daily integrated string output energy in Wh |
| 99 | 1 | In1DCA | int16 | R | String input 1 current in mA |
| 100 | 1 | In2DCA | int16 | R | String input 2 current in mA |
| 2 | |||||
| 101 | 1 | String ID | int16 | R | The string number |
| 102 | 2 | Reserved | - | - | |
| 104 | 2 | String data timestamp | uint32 | R | The UTC timestamp of the measurements |
| 106 | 1 | OutDCA | int16 | R | String output current in mA |
| 107 | 2 | OutDCV | uint32 | R | String output voltage in mV |
| 109 | 2 | In1DCV | uint32 | R | String input 1 voltage in mV |
| 111 | 2 | In2DCV | uint32 | R | String input 2 voltage in mV |
| 113 | 2 | DCWh | uint32 | R | Daily integrated string output energy in Wh |
| 115 | 1 | In1DCA | int16 | R | String input 1 current in mA |
| 116 | 1 | In2DCA | int16 | R | String input 2 current in mA |