All register values look like large raw integers. What is wrong?

SunSpec Model 101 uses paired scale factor registers (for example a_sf, w_sf, v_sf). Each raw integer must be multiplied by 10 raised to the power of its matching scale factor. A raw value of 2310 with v_sf of -1 equals 231.0 V. Confirm the ModbusCloud portal is applying scale factors automatically and has not received a NOT_IMPLEMENTED marker value from the device.

Phase B and C voltage registers read zero on a single-phase inverter. Is that a wiring fault?

No. For a device reporting SunSpec DID 101, only phase A registers are populated. Registers aphb, aphc, ppvphbc, ppvphca, phvphb, and phvphc will read zero or return a NOT_IMPLEMENTED value. This is correct SunSpec behaviour and does not indicate a hardware or wiring problem.

The gateway connects but no values appear after importing the template.

First confirm the inverter's Modbus TCP server is active: the inverter must be in a powered-on state, not sleeping or in night-time shutdown. SunSpec devices also require a valid model block start address: the map may begin at register 0, 40000, or 50000 depending on the device. Verify the base address in the portal matches the device's actual map offset, and check that the unit ID is correct.

The st register shows an unexpected value. What do the state codes mean?

The SunSpec operating state enumeration defines: 1 = Off, 2 = Sleeping, 3 = Grid Monitoring, 4 = Producing, 5 = Throttled, 6 = Shutting Down, 7 = Fault, 8 = Standby. If the state is 7 (Fault), check the evt1 bitfield for standard fault flags such as GROUND_FAULT, OVER_TEMP, or AC_DISCONNECT. Vendor-specific detail is in stvnd and the evtvnd registers.

Free Modbus template: SunSpec Model 101 — Inverter (Single Phase)

Name: SunSpec Model 101 — Inverter (Single Phase)
Brand: SunSpec
SKU: a197f3f0-c272-47eb-9d42-08bdf4eff97c

SunSpec Model 101 is an open, manufacturer-independent Modbus register specification for single-phase PV inverters, used across certified devices from many vendors. This template reads the full Model 101 block over Modbus TCP: AC current, per-phase voltages, real and reactive power, power factor, cumulative energy, DC input current and voltage, four temperature sensors, and the inverter operating state. Companion models SunSpec Model 102 (split-phase) and SunSpec Model 103 (three-phase) share the same block layout. Every numeric value pairs with a signed scale factor register, so one template covers devices regardless of their internal resolution. This makes cross-vendor PV monitoring consistent and fast to deploy.

Registers (45)

45 read / 0 write

Name	Address	Function	Type	Unit	Access
id SunSpec model identifier, value 101 for single-phase inverter.	•••	•••	•••		R
l Model block length in Modbus registers following this field.	•••	•••	•••		R
a Total AC output current across all phases, amperes.	•••	•••	•••	A	R
apha AC current on phase A, amperes.	•••	•••	•••	A	R
aphb AC current on phase B, amperes.	•••	•••	•••	A	R
aphc AC current on phase C, amperes.	•••	•••	•••	A	R
a_sf Scale factor exponent applied to all current registers.	•••	•••	•••		R
ppvphab Line-to-line voltage between phases A and B, volts.	•••	•••	•••	V	R
ppvphbc Line-to-line voltage between phases B and C, volts.	•••	•••	•••	V	R
ppvphca Line-to-line voltage between phases C and A, volts.	•••	•••	•••	V	R
phvpha Phase A voltage to neutral, volts.	•••	•••	•••	V	R
phvphb Phase B voltage to neutral, volts.	•••	•••	•••	V	R
phvphc Phase C voltage to neutral, volts.	•••	•••	•••	V	R
v_sf Scale factor exponent applied to all voltage registers.	•••	•••	•••		R
w AC real power output, watts, signed.	•••	•••	•••	W	R
w_sf Scale factor exponent applied to the AC power register.	•••	•••	•••		R
hz AC grid frequency, hertz.	•••	•••	•••	Hz	R
hz_sf Scale factor exponent applied to the frequency register.	•••	•••	•••		R
va AC apparent power, volt-amperes, signed.	•••	•••	•••	VA	R
va_sf Scale factor exponent applied to the apparent power register.	•••	•••	•••		R
var AC reactive power, var, signed.	•••	•••	•••	var	R
var_sf Scale factor exponent applied to the reactive power register.	•••	•••	•••		R
pf AC power factor as a percentage, signed.	•••	•••	•••	Pct	R
pf_sf Scale factor exponent applied to the power factor register.	•••	•••	•••		R
wh Cumulative AC energy produced, watt-hours, accumulating counter.	•••	•••	•••	Wh	R
wh_sf Scale factor exponent applied to the energy register.	•••	•••	•••		R
dca DC input current from the PV array, amperes.	•••	•••	•••	A	R
dca_sf Scale factor exponent applied to the DC current register.	•••	•••	•••		R
dcv DC input voltage from the PV array, volts.	•••	•••	•••	V	R
dcv_sf Scale factor exponent applied to the DC voltage register.	•••	•••	•••		R
dcw DC input power from the PV array, watts, signed.	•••	•••	•••	W	R
dcw_sf Scale factor exponent applied to the DC power register.	•••	•••	•••		R
tmpcab Inverter cabinet internal temperature, degrees Celsius.	•••	•••	•••	°C	R
tmpsnk Heat sink temperature, degrees Celsius.	•••	•••	•••	°C	R
tmptrns Transformer temperature, degrees Celsius.	•••	•••	•••	°C	R
tmpot Other internal temperature sensor, degrees Celsius.	•••	•••	•••	°C	R
tmp_sf Scale factor exponent applied to all temperature registers.	•••	•••	•••		R
st Inverter operating state per SunSpec enumeration.	•••	•••	•••		R
stvnd Vendor-defined operating state code, manufacturer-specific.	•••	•••	•••		R
evt1 Standard event flags bitfield, bits 0 to 31.	•••	•••	•••		R
evt2 Standard event flags bitfield, bits 32 to 63.	•••	•••	•••		R
evtvnd1 Vendor-defined event flags bitfield, bits 0 to 31.	•••	•••	•••		R
evtvnd2 Vendor-defined event flags bitfield, bits 32 to 63.	•••	•••	•••		R
evtvnd3 Vendor-defined event flags bitfield, bits 64 to 95.	•••	•••	•••		R
evtvnd4 Vendor-defined event flags bitfield, bits 96 to 127.	•••	•••	•••		R

Loading registers…

SunSpec Model 101 — Inverter (Single Phase)

Overview

Use cases

Installation

Things to watch for

Registers (45)

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