The gateway connects but both registers return zero or no data.

Confirm the Modbus address on the inverter display matches the unit ID set in the portal. The default Sungrow SG Series address is 1. Also verify the inverter is in grid-connected running state: registers return meaningful values only when the inverter is actively producing power or has logged generation history.

The power register at 5082 shows a negative or unexpected value.

Address 5082 is typed as int32 in this template. Some Sungrow SG firmware revisions return the active power as a signed value where negative indicates import or standby. Cross-check with the inverter display. Also note that the Sungrow protocol uses little-endian word order for 32-bit registers, so ensure your gateway or polling tool applies the correct byte-swap order.

RS485 wiring is connected but I get CRC errors or timeouts on every poll.

Check that only one master is polling the bus at a time. Verify A/B polarity is not reversed at either end. Sungrow RS485 runs at 9600 bps by default; if the baud rate on the inverter has been changed, update the ModbusCloud Gateway serial settings to match. Add a 120-ohm termination resistor at each end of long cable runs.

The energy register at 5098 rolls back to zero unexpectedly after a firmware update.

Sungrow SG Series firmware updates can occasionally reset non-volatile energy counters. If you observe a rollback, note the reading before and after the update and apply a manual offset in the portal dashboard to preserve historical totals. Contact Sungrow support if the reset is not documented in the firmware release notes.

Free Modbus template: Sungrow SG Series Inverter (grid)

The Sungrow SG Series Inverter is a PV grid-connected string inverter used in residential and commercial solar installations. This ModbusCloud template targets the SG Series grid variant and reads two core registers over Modbus RTU via RS485: instantaneous active power output (address 5082) and cumulative energy generation (address 5098). Both are 32-bit values polled using function code 4. With these two registers live in your portal, you can track real-time generation and long-run yield from any SG Series unit without manual data retrieval.

Name	Address	Function	Type	Unit	Access
power Instantaneous active power output of the inverter, signed integer.	5082	FC04	int32	W	R
energy Cumulative total AC energy generated, unsigned 32-bit value.	5098	FC04	uint32	Wh	R