SunSpec Model 202 — split single phase (ABN) meter
SunSpec Model 202 is an open-standard AC meter model defined by the SunSpec Alliance for split single-phase (ABN) installations. This Modbus TCP template reads the full set of per-phase and aggregate measurements: current, voltage (line-to-neutral and line-to-line), frequency, real power, apparent power, reactive power, power factor, and four-quadrant cumulative energy totals for both import and export. All numeric values are scaled by companion scaling-factor registers that must be applied at read time. The template also exposes the event bitfield for fault monitoring. Import it into your ModbusCloud portal to get immediate visibility into any SunSpec-compliant split-phase meter.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 74, read only
- Brand
- SunSpec
- Compatible models
- SunSpec Model 203 — wye-connect three phase (abcn) meter · SunSpec Model 204 — delta-connect three phase (abc) meter
- Last updated
Registers (74)
74 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| id | Read | ||||
| l | Read | ||||
| a | A | Read | |||
| apha | A | Read | |||
| aphb | A | Read | |||
| aphc | A | Read | |||
| a_sf | Read | ||||
| phv | V | Read | |||
| phvpha | V | Read | |||
| phvphb | V | Read | |||
| phvphc | V | Read | |||
| ppv | V | Read | |||
| phvphab | V | Read | |||
| phvphbc | V | Read | |||
| phvphca | V | Read | |||
| v_sf | Read | ||||
| hz | Hz | Read | |||
| hz_sf | Read | ||||
| w | W | Read | |||
| wpha | W | Read | |||
| wphb | W | Read | |||
| wphc | W | Read | |||
| w_sf | Read | ||||
| va | VA | Read | |||
| vapha | VA | Read | |||
| vaphb | VA | Read | |||
| vaphc | VA | Read | |||
| va_sf | Read | ||||
| var | var | Read | |||
| varpha | var | Read | |||
| varphb | var | Read | |||
| varphc | var | Read | |||
| var_sf | Read | ||||
| pf | Pct | Read | |||
| pfpha | Pct | Read | |||
| pfphb | Pct | Read | |||
| pfphc | Pct | Read | |||
| pf_sf | Read | ||||
| totwhexp | Wh | Read | |||
| totwhexppha | Wh | Read | |||
| totwhexpphb | Wh | Read | |||
| totwhexpphc | Wh | Read | |||
| totwhimp | Wh | Read | |||
| totwhimppha | Wh | Read | |||
| totwhimpphb | Wh | Read | |||
| totwhimpphc | Wh | Read | |||
| totwh_sf | Read | ||||
| totvahexp | VAh | Read | |||
| totvahexppha | VAh | Read | |||
| totvahexpphb | VAh | Read | |||
| totvahexpphc | VAh | Read | |||
| totvahimp | VAh | Read | |||
| totvahimppha | VAh | Read | |||
| totvahimpphb | VAh | Read | |||
| totvahimpphc | VAh | Read | |||
| totvah_sf | Read | ||||
| totvarhimpq1 | varh | Read | |||
| totvarhimpq1pha | varh | Read | |||
| totvarhimpq1phb | varh | Read | |||
| totvarhimpq1phc | varh | Read | |||
| totvarhimpq2 | varh | Read | |||
| totvarhimpq2pha | varh | Read | |||
| totvarhimpq2phb | varh | Read | |||
| totvarhimpq2phc | varh | Read | |||
| totvarhexpq3 | varh | Read | |||
| totvarhexpq3pha | varh | Read | |||
| totvarhexpq3phb | varh | Read | |||
| totvarhexpq3phc | varh | Read | |||
| totvarhexpq4 | varh | Read | |||
| totvarhexpq4pha | varh | Read | |||
| totvarhexpq4phb | varh | Read | |||
| totvarhexpq4phc | varh | Read | |||
| totvarh_sf | Read | ||||
| evt | Read |
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Use cases
- Monitor real-time import and export power per phase to detect load imbalances in split-phase residential or light-commercial installations.
- Track cumulative exported watt-hours over time to verify solar feed-in totals against utility billing data.
- Alert on unexpected reactive power spikes on individual phases to identify poorly corrected inductive loads.
- Compare per-phase power factor readings to spot deteriorating power quality and schedule corrective maintenance.
- Monitor the event bitfield register to receive early warnings of meter fault conditions without manual inspection.
Installation
Enable Modbus TCP on the physical meter: open the device web interface or front-panel menu, navigate to the communication or Modbus section, and activate Modbus TCP on port 502.
Connect the meter to the same LAN segment as the ModbusCloud Gateway, confirm the meter has a static IP address, and note the IP and unit ID assigned in the meter configuration.
In your ModbusCloud portal, add a new gateway, then import the SunSpec Model 202 template and enter the meter's IP address and unit ID; set the poll interval to match your logging requirements.
Verify the connection by spot-checking the 'a' (total current) and 'w' (total real power) registers in the live register view; apply the corresponding scaling factors 'a_sf' and 'w_sf' to confirm values match local meter readout.
Things to watch for
Register values look like large raw integers. What is wrong?
SunSpec integer meter models use companion scaling-factor registers to represent the implied decimal point. For example, multiply the 'w' value by 10 raised to the power of 'w_sf' to get watts. Always read the scaling-factor register in the same poll cycle as the measurement register, because scaling factors can change dynamically.
The gateway connects but all registers return zero or 0x8000 (not-implemented).
A value of 0x8000 (for int16) or 0xFFFF (for uint16) is the SunSpec not-implemented sentinel, meaning that register is not populated by the specific physical meter. Confirm the meter actually implements Model 202 by reading the 'id' register at offset 0 and checking that it returns 202. Also verify the correct base address offset is configured in the portal.
Cumulative energy totals 'totwhimp' and 'totwhexp' are not incrementing.
Confirm the meter CT orientation is correct for the split-phase ABN topology: reversed CTs cause the meter to attribute import as export. Also check that 'totwh_sf' is negative (which is typical), meaning the raw uint32 value must be divided rather than multiplied. Verify you are not reading the 32-bit register across two separate poll requests, which can introduce split-read errors.
The 'evt' register shows a non-zero value. What does this mean?
The 'evt' register is a 32-bit bitfield where each bit corresponds to a specific meter event or fault condition as defined in the SunSpec meter specification. A non-zero value indicates at least one active event. Cross-reference the set bits against the SunSpec meter event flag definitions to identify the specific condition. Set up a ModbusCloud portal alert on this register so any future fault is flagged immediately.
Knowledge base articles for this device
SunSpec Modbus: one register map for many inverters
SunSpec Modbus is the open register map SMA, Fronius, SolarEdge and Kostal share. The layout, int+SF vs float, the TCP port per brand and reading a mixed fleet.
Fronius Modbus: read a Symo GEN24 over Modbus TCP
Fronius Modbus explained: enable Modbus TCP on the Symo GEN24 on port 502, choose between int+SF and float, read the right SunSpec registers and scale them correctly. Practical guide for solar installers.
SMA Modbus: reading a Sunny Boy over Modbus TCP (installers)
SMA Modbus explained: enable the Modbus TCP server on port 502, choose between the SMA profile (unit ID 3) and SunSpec (unit ID 126), read the right registers, and handle the NaN values at night. Practical guide for installers.
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