SunSpec Model 201 — Meter (Single Phase) single phase (AN or AB) meter
SunSpec Model 201 defines the open interoperability standard for single-phase (AN or AB) AC energy meters used in distributed energy resource systems. This template reads the complete Model 201 register block over Modbus TCP, covering instantaneous current, voltage (line-to-neutral and line-to-line), frequency, real power, apparent power, reactive power, and power factor. Cumulative energy totals for import and export are tracked per phase across all four reactive quadrants. The event register surfaces meter fault flags. Importing this template into your ModbusCloud portal gives you a structured, vendor-neutral view of any SunSpec-certified single-phase meter on your network.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 74, read only
- Brand
- SunSpec
- 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 | |||
| ppvphab | V | Read | |||
| ppvphbc | V | Read | |||
| ppvphca | 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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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Monitor total real energy imported and exported daily to verify net metering settlements with the grid operator.
- Track phase A power factor over time to detect reactive load imbalances that increase grid tariff charges.
- Alert on the event register bitmask to catch meter fault conditions before they distort billing or monitoring data.
- Compare instantaneous real power against apparent power to report kVA demand peaks for capacity planning.
- Verify grid frequency readings stay within the 50 Hz tolerance band required by your local grid code.
Installation
Enable Modbus TCP on your SunSpec-certified meter by navigating to the communication or network settings section in its web interface or front-panel menu, then note the assigned IP address and port (default 502).
Connect the meter to the same LAN segment as the ModbusCloud Gateway, confirm network reachability with a ping, and ensure no firewall rules block port 502.
In your ModbusCloud portal, add the Gateway, then import the SunSpec Model 201 template and assign the unit ID that matches the meter's configured Modbus device address (commonly 1 for TCP).
Trigger a live poll in the portal and spot-check the 'w' register for a plausible real power reading, then verify 'hz' shows approximately 50 or 60 Hz to confirm correct scaling.
Things to watch for
Why do all my power and energy readings look wrong or wildly scaled?
SunSpec Model 201 uses signed scale factors (sunssf) that shift the decimal point left or right. Your application must always read the corresponding '_sf' register alongside each measurement group and apply the exponent. Skipping this step produces values that are off by factors of 10, 100, or 1000. Always read measurement registers and their scale factor registers in the same Modbus request.
The gateway connects but phase B and C registers return zero or 0xFFFF. Why?
SunSpec Model 201 is a single-phase model. Phase B and C per-phase registers are present in the map but return the SunSpec 'not implemented' value (0x8000 for int16, 0x80000000 for uint32) on true single-phase meters. This is expected behavior, not a wiring fault. Only summary and phase A registers carry live data on AN or AB configurations.
My meter is on the network but the portal shows no data at all.
First confirm the meter's Modbus TCP server is enabled in its communication settings, as many meters ship with it disabled by default. Next, verify the unit ID in the portal matches the meter's configured device address. Finally, check that the SunSpec model starts at the correct base register offset on your specific meter, as some manufacturers place Model 201 after a Common Model block whose length varies.
The evt register is non-zero. What does that mean and should I act on it?
The 'evt' register is a bitmask where each bit represents a distinct meter fault or anomaly flag as defined by the SunSpec Alliance specification. A non-zero value indicates at least one active condition. Consult the SunSpec meter event flag definitions and your meter's documentation to decode which bits are set. Persistent non-zero values may indicate wiring faults, voltage out-of-range, or frequency anomalies that can compromise measurement accuracy.
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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