Solarlog Solarlog (grid)

Installation

1. 1Enable the Modbus TCP free interface on the Solarlog device by navigating to Configuration, then Digital Interfaces, and activating Modbus TCP on port 502.
2. 2Connect the ModbusCloud Gateway to the same LAN as the Solarlog device and confirm IP reachability by pinging the Solarlog address from the network.
3. 3In the ModbusCloud portal, add the Gateway, import the Solarlog Solarlog (grid) template, and set the Modbus unit ID to match the Solarlog configuration (default is typically 1).
4. 4Spot-check register 3502 in the portal live-data view and confirm the watt value matches the figure shown on the Solarlog web interface under current generation.

Things to watch for

01

Why do power_a and power_b return obviously wrong or huge values?

The Solarlog uses a mixed byte order for 32-bit values: bytes within each 16-bit word are Big-Endian, but the two words of a 32-bit value are stored Little-Endian (low word first, high word second). If your client reads them as standard Big-Endian uint32, the result will be wrong. Ensure the ModbusCloud template applies the correct word-swap interpretation for both registers.

02

The gateway connects but both registers return zero constantly.

The Modbus TCP free interface on the Solarlog only reports non-zero values when at least one inverter is communicating with the logger. Verify that the Solarlog web interface shows live inverter data. Also confirm that the free Modbus TCP interface is enabled and not the licensed PM interface, which uses a different register map.

03

Readings update very slowly or appear frozen in the portal.

The Solarlog refreshes its internal data every 15 to 60 seconds depending on configuration. Modbus reads between refresh cycles return the last cached value, not a real-time sample. This is normal device behaviour. Adjust your polling interval in ModbusCloud to 60 seconds to stay in sync with the Solarlog update cycle.

04

Connection is refused on port 502. What should I check?

The Solarlog free Modbus TCP interface listens on port 502 only when explicitly enabled in the device configuration under Digital Interfaces. Verify the feature is active in the Solarlog web UI. Also check that no firewall on the local network blocks port 502 between the ModbusCloud Gateway and the Solarlog IP address.

Registers (2)

2 read / 0 write

More Solarlog templates

Solarlog Solarlog (pv)

Solarlog

Modbus TCP

2 registers

Solarlog Solarlog

Solarlog

Modbus TCP

22 registers

SolarLog Data Reading via Modbus TCP

Solarlog

Modbus TCP

Reads solar plant data from SolarLog data loggers via Modbus TCP.

17 registers70

More TCP templates

Sigenergy SigenStore EC (grid)

Sigenergy

Modbus TCP

5 registers1

Domekt R 400 V

Komfovent

Modbus TCP

Controls Komfovent Domekt recuperator ventilation via Modbus TCP

25 registers118

Algodue Energy meter UEM80-2D E

Algodue Elettronica S.r.l.

Modbus TCP

Measures single-phase energy consumption and production via Modbus TCP.

12 registers46

NIBE Nibe S-Series (SG Ready)

NIBE

Modbus TCP

5 registers1

Fronius - Modbus TCP

Fronius

Modbus TCP

Monitors Fronius Symo and Primo inverters via Modbus TCP

15 registers597

Siemens Junelight Smart Battery (battery)

Siemens

Modbus TCP

2 registers1