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.	0	FC03	uint16		R
l Model block length in Modbus registers following this field.	1	FC03	uint16		R
a Total AC output current across all phases, amperes.	2	FC03	uint16	A	R
apha AC current on phase A, amperes.	3	FC03	uint16	A	R
aphb AC current on phase B, amperes.	4	FC03	uint16	A	R
aphc AC current on phase C, amperes.	5	FC03	uint16	A	R
a_sf Scale factor exponent applied to all current registers.	6	FC03	int16		R
ppvphab Line-to-line voltage between phases A and B, volts.	7	FC03	uint16	V	R
ppvphbc Line-to-line voltage between phases B and C, volts.	8	FC03	uint16	V	R
ppvphca Line-to-line voltage between phases C and A, volts.	9	FC03	uint16	V	R
phvpha Phase A voltage to neutral, volts.	10	FC03	uint16	V	R
phvphb Phase B voltage to neutral, volts.	11	FC03	uint16	V	R
phvphc Phase C voltage to neutral, volts.	12	FC03	uint16	V	R
v_sf Scale factor exponent applied to all voltage registers.	13	FC03	int16		R
w AC real power output, watts, signed.	14	FC03	int16	W	R
w_sf Scale factor exponent applied to the AC power register.	15	FC03	int16		R
hz AC grid frequency, hertz.	16	FC03	uint16	Hz	R
hz_sf Scale factor exponent applied to the frequency register.	17	FC03	int16		R
va AC apparent power, volt-amperes, signed.	18	FC03	int16	VA	R
va_sf Scale factor exponent applied to the apparent power register.	19	FC03	int16		R
var AC reactive power, var, signed.	20	FC03	int16	var	R
var_sf Scale factor exponent applied to the reactive power register.	21	FC03	int16		R
pf AC power factor as a percentage, signed.	22	FC03	int16	Pct	R
pf_sf Scale factor exponent applied to the power factor register.	23	FC03	int16		R
wh Cumulative AC energy produced, watt-hours, accumulating counter.	24	FC03	uint32	Wh	R
wh_sf Scale factor exponent applied to the energy register.	26	FC03	int16		R
dca DC input current from the PV array, amperes.	27	FC03	uint16	A	R
dca_sf Scale factor exponent applied to the DC current register.	28	FC03	int16		R
dcv DC input voltage from the PV array, volts.	29	FC03	uint16	V	R
dcv_sf Scale factor exponent applied to the DC voltage register.	30	FC03	int16		R
dcw DC input power from the PV array, watts, signed.	31	FC03	int16	W	R
dcw_sf Scale factor exponent applied to the DC power register.	32	FC03	int16		R
tmpcab Inverter cabinet internal temperature, degrees Celsius.	33	FC03	int16	C	R
tmpsnk Heat sink temperature, degrees Celsius.	34	FC03	int16	C	R
tmptrns Transformer temperature, degrees Celsius.	35	FC03	int16	C	R
tmpot Other internal temperature sensor, degrees Celsius.	36	FC03	int16	C	R
tmp_sf Scale factor exponent applied to all temperature registers.	37	FC03	int16		R
st Inverter operating state per SunSpec enumeration.	38	FC03	uint16		R
stvnd Vendor-defined operating state code, manufacturer-specific.	39	FC03	uint16		R
evt1 Standard event flags bitfield, bits 0 to 31.	40	FC03	uint32		R
evt2 Standard event flags bitfield, bits 32 to 63.	42	FC03	uint32		R
evtvnd1 Vendor-defined event flags bitfield, bits 0 to 31.	44	FC03	uint32		R
evtvnd2 Vendor-defined event flags bitfield, bits 32 to 63.	46	FC03	uint32		R
evtvnd3 Vendor-defined event flags bitfield, bits 64 to 95.	48	FC03	uint32		R
evtvnd4 Vendor-defined event flags bitfield, bits 96 to 127.	50	FC03	uint32		R

SunSpec Model 101 — Inverter (Single Phase)

Overview

Use cases

Installation

Things to watch for

Registers (45)

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