Why does the power register always read zero or a fixed value?

The power register at address 16545 is a signed int16. If the inverter is in standby or nighttime mode it may legitimately return zero. Confirm the inverter is actively operating, check that the Modbus unit ID in the portal matches the inverter setting, and verify port 502 is reachable from the Gateway.

The energy counter value looks implausibly large. What is wrong?

Register 16637 is a uint32 spanning two consecutive 16-bit Modbus registers. If only one word is read, the value will appear either truncated or doubled. Confirm the template is configured to read two registers for this address and that the word order matches the inverter's big-endian convention, which is standard for SAJ devices.

The Gateway connects but no data appears in the portal. What should I check?

First confirm the inverter's communication module (AIO3 dongle or built-in LAN) is on the same subnet as the Gateway. Then verify the inverter's Modbus TCP setting is active, not set to RTU-only mode. SAJ inverters may revert to a default communication state after a firmware update or power cycle, so check the communication settings again after any restart.

The inverter is reachable but readings drop out intermittently. Why?

SAJ H1 Series inverters can close idle TCP connections after a short timeout. If the polling interval in the ModbusCloud portal exceeds the inverter's keep-alive window, the Gateway must re-establish the connection each poll cycle. Reducing the polling interval or configuring a shorter timeout on the Gateway side typically resolves intermittent dropouts.

Free Modbus template: SAJ H1 Series Hybrid Solar Inverter (grid)

The SAJ H1 Series is a single-phase hybrid solar inverter designed for residential and small-commercial energy storage systems, combining PV generation, battery management, and grid interaction in one unit. This Modbus TCP template reads two key grid-side registers from the SAJ H1 Series: instantaneous active grid power and a cumulative energy counter. Connecting via the ModbusCloud Gateway, these readings give installers and building owners a live and historical view of grid exchange, supporting energy reporting and anomaly detection without requiring cloud access through SAJ's own portal.

Name	Address	Function	Type	Unit	Access
power Instantaneous active grid power, signed, in watts.	16545	FC03	int16	W	R
energy Cumulative energy counter, unsigned 32-bit, no unit scaling.	16637	FC03	uint32		R