Installation · Sofar Solar

Install GridZeno on Sofar KTLM.

Sofar KTLM-G3 is a single-phase grid inverter without a battery, so GridZeno can show the production and, where the protocol allows it, limit export. There's no battery to control. The dongle is connected with two wires in the 16-pin COM connector, pins 1 and 3, which Sofar has set aside for monitoring.

Applies to: SOFAR 3-6KTLM-G3
Connection: Wires in the inverter's terminal plug
Time: About 30 minutes

A grid inverter without a battery. GridZeno shows solar, consumption and grid and lowers the inverter's export limit at negative prices. What GridZeno can do on Sofar KTLM

How the dongle recognises it: The serial number in holding 0x0445 with the code H3 (3-6KTLM-G3), H4 (7.5KTLM-G3) or T1 (7-10.5KTLM-G3), single-phase. The 3-6KTLM-G2 (H1) uses Sofar's older protocol and isn't recognised.

GridZeno Dongle for Sofar KTLM

What you need

GridZeno Dongle: The device ID is on the label, e.g. GZ-A1B2C3.
Cable: GridZeno's Modbus cable with one end cut off, or another network cable with one plug.
Wire strippers and ferrules: Two wire ferrules for the two wires in the COM connector from the accessory bag.
USB power: A 5 V USB charger and a cable with USB-C.

The port

On the underside of the inverter, next to the USB port and the AC output. The same connector is used for energy meter, current clamp and DRM, so there may already be wires in it.

Port: COM (16-pin multifunction connector)

The COM connector, as Sofar numbers the pins. Pins 1 and 2 are A, pins 3 and 4 are B, so several inverters can be daisy-chained. The numbers are on the plug.

Pin 1 A, 485_TX+
Pin 3 B, 485_TX-

The cable

A network cable where one end has an RJ45 plug for the dongle and the other end is cut off. At the inverter end, only the two wires from pins 4 and 5 are used, with terminals on. Pin 7 in COM belongs to the DRM control, not to RS485, so the white/green wire isn't used.

From the dongle to the inverter
Dongle end	Inverter end
Dongle pin 4, blue (A)	COM pin 1, 485_TX+
Dongle pin 5, white/blue (B)	COM pin 3, 485_TX-
The other wires	Cut off and insulated

Settings

On the inverter

1.Enter Setting > 7.Set Address: 01, as from the factory

In GridZeno's Welcome

The inverter is chosen in GridZeno: in Welcome the first time, and later under System, Change inverter. The dongle fetches its setup from there.

Manufacturer and model: Sofar Solar, KTLM
Connection: By cable (RS485)
RS485 settings: Keep the default: 9600 baud, 8N1, address 1.

Step by step

Each step has a small drawing that shows what to do.

1
Check the address
Hold the button down to get into 1.Enter Setting, and go to 7.Set Address. The address must be 01, as from the factory. If the display asks for a password, Sofar's default is 0001.
2
Find the COM connector
The round 16-pin connector is on the underside by the USB port. Switch off the inverter, and take out the connector so you can get at the terminals.
3
Pass the cable through the connector's parts
Pass the cable through the connector's cable gland and waterproof cover before the wires are put in.
4
Prepare the cable
Strip the two wires from pin 4 (blue) and pin 5 (white/blue), and put terminals on. Insulate the other wires.
5
Insert the wires in pins 1 and 3
Blue (A) goes in pin 1 and white/blue (B) in pin 3, following the numbers on the connector. Pins 2 and 4 are for a possible next inverter in the chain.
6
Plug the connector back in
Tighten the screws in the cover and the cable gland, and plug the COM connector into the inverter so it's sealed.
7
Plug the RJ45 end into the dongle
The cable's other end goes into the dongle's RS485 port. Place the dongle somewhere dry and close to the inverter, so the cable doesn't hang from the plug.
8
Connect power to the dongle
Plug the USB-C cable into the dongle and the charger into a socket. The dongle starts by itself. It gets power from the charger, not from the inverter.
9
Connect the dongle to the network
Over Wi-Fi: the first time, the dongle creates its own Wi-Fi, GridZeno-Setup- followed by the last characters of the device ID. Connect your phone to it, choose your own network, enter the password, and press Save and connect. When it says Connection OK, press Go to GridZeno. Over cable (LAN): plug a network cable from the router into the dongle's network port.
10
Log in, and choose your inverter
Log in to GridZeno. Welcome pairs the dongle with its device ID. Then choose your inverter, Sofar Solar KTLM, and the connection By cable (RS485). Press Save inverter, and the dongle fetches its setup and reads the inverter.

The dongle's own setup is described with screenshots in The user guide, and the pairing in Getting started.

Take care

Pins 5 and 6 in COM are the energy meter's connection, pins 15 and 16 the current clamp's and pins 7 to 12 the DRM control. Don't touch them. The USB port is for Sofar's own data logger and for updates.

If you aren't used to fitting wires in a terminal connector, let the installer do it.

What GridZeno can control on Sofar KTLM, and how, is on the page about Sofar KTLM. If you're stuck, write to us with the model name.

Source

Ports, pins and menus are from the manufacturer's own manual: SOFAR 3K~6KTLM-G3 User manual (EN, version 2024-01-22), Section 4.5, Com port connection (table 4-3), 4.4.2, RS485 interface, and 6.3, Main Interface (7. Set address).