Why does the power register always read zero?

Modbus TCP is disabled by default on Sigenergy devices. Open the mySigen App, go to device settings, and confirm the Modbus TCP Server Enable toggle is active and saved. Also verify that port 502 is reachable from the Gateway by attempting a TCP connection to the inverter IP on that port.

The gateway connects but phase current registers return errors.

Phase current registers at addresses 31017, 31019, and 31021 are int32 values spanning two holding registers each. If your polling tool requests only one register per address, it will return an exception. Ensure your read request covers two registers (four bytes) per phase current address.

Energy values look wrong or jump unexpectedly between polls.

The energy register is a uint64 spanning four holding registers. Reading fewer than four consecutive registers will produce a truncated value. Confirm your Modbus client reads four registers starting at address 30562 and assembles them in big-endian order as documented in the Sigenergy Modbus protocol specification.

No data appears after importing the template. What should I check?

Confirm the ModbusCloud Gateway and the Sigen PV Max are on the same local network segment with no firewall blocking port 502. Also verify the unit ID in the portal matches the slave address configured in the mySigen App, and that Remote EMS Scheduling is enabled in the inverter's communication settings.

Free Modbus template: Sigenergy Sigen PV Max (grid)

The Sigenergy Sigen PV Max is a string PV inverter with integrated grid-metering capability, used in residential and small commercial solar installations. This ModbusCloud template reads the device over Modbus TCP and collects the grid-side active power, cumulative imported energy, and per-phase currents on phases A, B, and C. Together these registers give a complete picture of what the installation draws from or feeds to the grid at any moment. Compatible with Sigen Hybrid and SigenStore EC systems sharing the same register map, the template lets installers verify grid balance and feed-in behaviour directly from the ModbusCloud portal.

Name	Address	Function	Type	Unit	Access
power Grid active power at the system checkpoint, positive imports, negative exports.	30005	FC03	int32	W	R
energy Cumulative energy measured at the grid connection point.	30562	FC03	uint64	Wh	R
currents_a AC current on grid phase A.	31017	FC03	int32	A	R
currents_b AC current on grid phase B.	31019	FC03	int32	A	R
currents_c AC current on grid phase C.	31021	FC03	int32	A	R

Sigenergy Sigen PV Max (grid)

Overview

Use cases

Installation

Things to watch for

Registers (5)

Working with Modbus in your projects?

Free: RS485 and Modbus RTU installation checklist (PDF)

More Sigenergy templates

Sigenergy SigenStore EC (grid)

Sigenergy Sigen PV Max (battery)

Sigenergy Sigen Hybrid (pv)

Sigenergy SigenStor Plant

Sigenergy SigenStor Slave

Sigenergy Sigen Hybrid (grid)

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