Why do actvarhq1 through actvarhq4 all read zero?

Many inverters only increment reactive energy quadrant counters when reactive power control is actively engaged. If the inverter runs at unity power factor with no Q setpoint active, all four quadrant accumulators will remain zero. Enable a reactive power mode in the inverter to confirm the registers respond.

The gateway connects but id and l return unexpected values. What now?

SunSpec models are discovered dynamically: the actual Modbus address of Model 122 is not fixed and depends on how many models precede it in the device map. The template uses relative offsets from the model header. If absolute addresses are used instead, reads will land in the wrong model. Confirm the template is configured for relative addressing starting at the model id register.

Isolation resistance register ris reads NaN or 65535. Is the sensor faulty?

A NaN value in ris is normal when the inverter does not support isolation resistance measurement or when the measurement is unavailable at night with no DC voltage present. Check the inverter datasheet to confirm whether Ris is implemented, and verify DC strings are energized before expecting a valid reading.

Timestamp register tms shows a value far in the past. What is wrong?

tms counts seconds since 2000-01-01 00:00 UTC. If the inverter clock has never been synchronized, it may report a very low count. Verify that the inverter time synchronization source shown in tmsrc is active and reachable. Correct timekeeping is important for aligning energy logs with external billing or monitoring systems.

Free Modbus template: SunSpec Model 122 — Measurements_Status

Name: SunSpec Model 122 — Measurements_Status
Brand: SunSpec
SKU: 42adef18-da0f-424d-b576-089a99d7eecf

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Free Modbus template: SunSpec Model 122 — Measurements_Status | ModbusCloud

Registers (22)

22 read / 0 write

Name	Address	Function	Type	Unit	Access
id SunSpec model identifier, fixed value 122 for this model.	0	FC03	uint16		R
l Length of this model block in Modbus registers.	1	FC03	uint16		R
pvconn PV inverter connection status: connected, available, in operation.	2	FC03	bool		R
storconn Storage inverter connection status: connected, available, in operation.	3	FC03	bool		R
ecpconn ECP grid connection status, bit 0 indicates connected.	4	FC03	bool		R
actwh Lifetime cumulative AC active energy output, watt-hours.	5	FC03	uint64	Wh	R
actvah Lifetime cumulative AC apparent energy output, volt-ampere-hours.	9	FC03	uint64	VAh	R
actvarhq1 Lifetime cumulative AC reactive energy, quadrant 1, var-hours.	13	FC03	uint64	varh	R
actvarhq2 Lifetime cumulative AC reactive energy, quadrant 2, var-hours.	17	FC03	uint64	varh	R
actvarhq3 Lifetime cumulative AC reactive energy, quadrant 3, var-hours.	21	FC03	uint64	varh	R
actvarhq4 Lifetime cumulative AC reactive energy, quadrant 4, var-hours.	25	FC03	uint64	varh	R
varaval Currently available reactive power capacity, vars.	29	FC03	int16	var	R
varaval_sf Scale factor exponent for varaval, signed integer.	30	FC03	int16		R
waval Currently available active power capacity, watts.	31	FC03	uint16	var	R
waval_sf Scale factor exponent for waval, signed integer.	32	FC03	int16		R
stsetlimmsk Bitmask indicating which setpoint limits are currently reached.	33	FC03	uint32		R
stactctl Bitmask of currently active inverter control modes, e.g. FixedW, Volt-VAr.	35	FC03	uint32		R
tmsrc Time synchronization source identifier, returned as a URL string.	37	FC03	string		R
tms Seconds elapsed since 2000-01-01 00:00 UTC, inverter timestamp.	41	FC03	uint32	Secs	R
rtst Ride-through status flag, indicates active LVRT or HVRT condition.	43	FC03	bool		R
ris Isolation resistance between PV array and ground, ohms.	44	FC03	uint16	ohms	R
ris_sf Scale factor exponent for ris, signed integer.	45	FC03	int16		R