The id register returns a value other than 4. Why?

The SunSpec model map on the device may place Model 4 at a different base offset than address 0 in your portal configuration. Scan the device's full SunSpec map to locate the actual base address of Model 4 and adjust the template offset accordingly.

All val registers read as 0xFFFF. What does this mean?

A value of 0xFFFF (65535) for a uint16 is the SunSpec 'Not Implemented' sentinel. This indicates the device has not populated those payload slots for the current request. Check the sts register first: a non-zero status code means the device returned an error rather than valid data.

The gateway connects but the ts register shows an implausible timestamp. What now?

The ts register is a 32-bit Unix epoch value spanning two consecutive 16-bit registers. Confirm the ModbusCloud template is reading it as uint32 across addresses 55 and 56. If the device clock is not synchronized to NTP, the timestamp will be arbitrary until time sync is restored.

Why does the seq counter not increment between polls?

Model 4 is a response model, not a polled data model. The seq counter increments only when the DER device issues a new secured dataset. If your polling interval is shorter than the device's dataset publication interval, you will read the same response multiple times. Align your poll rate with the device's update rate.

Free Modbus template: SunSpec Model 4 — Secure Dataset Read Response

Name: SunSpec Model 4 — Secure Dataset Read Response
Brand: SunSpec
SKU: 5a8c33cc-b792-4e01-a551-78cb42802c38

SunSpec Model 4 is a protocol-layer information model defined by the SunSpec Alliance for secure, tamper-evident Modbus TCP dataset reads from Distributed Energy Resource (DER) devices such as inverters and energy storage systems. The template reads the full response structure: a request sequence echo (rqseq), a status code (sts), up to 50 payload value registers (val1 through val50), a 32-bit Unix timestamp (ts) with millisecond resolution (ms), an outgoing sequence counter (seq), an alarm bitmap (alm), and the authentication algorithm identifier (alg) with its code length (n). For integrators verifying DER data integrity over Modbus TCP, this template provides the complete register map in one import.

Registers (61)

61 read / 0 write

Name	Address	Function	Type	Access
id SunSpec model identifier, fixed value 4 for this model.	0	FC03	uint16	R
l Length of this model block in registers.	1	FC03	uint16	R
rqseq Request sequence number echoed from the originating read request.	2	FC03	uint16	R
sts Response status code indicating success or error condition.	3	FC03	uint16	R
x Reserved padding register, not used by applications.	4	FC03	uint16	R
val1 Payload data word 1 from the secured dataset response.	5	FC03	uint16	R
val2 Payload data word 2 from the secured dataset response.	6	FC03	uint16	R
val3 Payload data word 3 from the secured dataset response.	7	FC03	uint16	R
val4 Payload data word 4 from the secured dataset response.	8	FC03	uint16	R
val5 Payload data word 5 from the secured dataset response.	9	FC03	uint16	R
val6 Payload data word 6 from the secured dataset response.	10	FC03	uint16	R
val7 Payload data word 7 from the secured dataset response.	11	FC03	uint16	R
val8 Payload data word 8 from the secured dataset response.	12	FC03	uint16	R
val9 Payload data word 9 from the secured dataset response.	13	FC03	uint16	R
val10 Payload data word 10 from the secured dataset response.	14	FC03	uint16	R
val11 Payload data word 11 from the secured dataset response.	15	FC03	uint16	R
val12 Payload data word 12 from the secured dataset response.	16	FC03	uint16	R
val13 Payload data word 13 from the secured dataset response.	17	FC03	uint16	R
val14 Payload data word 14 from the secured dataset response.	18	FC03	uint16	R
val15 Payload data word 15 from the secured dataset response.	19	FC03	uint16	R
val16 Payload data word 16 from the secured dataset response.	20	FC03	uint16	R
val17 Payload data word 17 from the secured dataset response.	21	FC03	uint16	R
val18 Payload data word 18 from the secured dataset response.	22	FC03	uint16	R
val19 Payload data word 19 from the secured dataset response.	23	FC03	uint16	R
val20 Payload data word 20 from the secured dataset response.	24	FC03	uint16	R
val21 Payload data word 21 from the secured dataset response.	25	FC03	uint16	R
val22 Payload data word 22 from the secured dataset response.	26	FC03	uint16	R
val23 Payload data word 23 from the secured dataset response.	27	FC03	uint16	R
val24 Payload data word 24 from the secured dataset response.	28	FC03	uint16	R
val25 Payload data word 25 from the secured dataset response.	29	FC03	uint16	R
val26 Payload data word 26 from the secured dataset response.	30	FC03	uint16	R
val27 Payload data word 27 from the secured dataset response.	31	FC03	uint16	R
val28 Payload data word 28 from the secured dataset response.	32	FC03	uint16	R
val29 Payload data word 29 from the secured dataset response.	33	FC03	uint16	R
val30 Payload data word 30 from the secured dataset response.	34	FC03	uint16	R
val31 Payload data word 31 from the secured dataset response.	35	FC03	uint16	R
val32 Payload data word 32 from the secured dataset response.	36	FC03	uint16	R
val33 Payload data word 33 from the secured dataset response.	37	FC03	uint16	R
val34 Payload data word 34 from the secured dataset response.	38	FC03	uint16	R
val35 Payload data word 35 from the secured dataset response.	39	FC03	uint16	R
val36 Payload data word 36 from the secured dataset response.	40	FC03	uint16	R
val37 Payload data word 37 from the secured dataset response.	41	FC03	uint16	R
val38 Payload data word 38 from the secured dataset response.	42	FC03	uint16	R
val39 Payload data word 39 from the secured dataset response.	43	FC03	uint16	R
val40 Payload data word 40 from the secured dataset response.	44	FC03	uint16	R
val41 Payload data word 41 from the secured dataset response.	45	FC03	uint16	R
val42 Payload data word 42 from the secured dataset response.	46	FC03	uint16	R
val43 Payload data word 43 from the secured dataset response.	47	FC03	uint16	R
val44 Payload data word 44 from the secured dataset response.	48	FC03	uint16	R
val45 Payload data word 45 from the secured dataset response.	49	FC03	uint16	R
val46 Payload data word 46 from the secured dataset response.	50	FC03	uint16	R
val47 Payload data word 47 from the secured dataset response.	51	FC03	uint16	R
val48 Payload data word 48 from the secured dataset response.	52	FC03	uint16	R
val49 Payload data word 49 from the secured dataset response.	53	FC03	uint16	R
val50 Payload data word 50 from the secured dataset response.	54	FC03	uint16	R
ts 32-bit Unix timestamp of when the dataset was captured.	55	FC03	uint32	R
ms Millisecond sub-second component of the dataset timestamp.	57	FC03	uint16	R
seq Outgoing sequence counter incremented with each new response.	58	FC03	uint16	R
alm Alarm bitmap indicating active alarm conditions at capture time.	59	FC03	uint16	R
alg Algorithm identifier used to compute the authentication code.	60	FC03	uint16	R
n Length in registers of the appended authentication code.	61	FC03	uint16	R