Installation · Growatt

Install GridZeno on Growatt MOD TL3-X3.

MOD TL3-X3 is Growatt's range of three-phase grid inverters without a battery, from 3 to 33 kW. They have only one signal connector, the round 4-pin COM connector. The dongle is connected with two wires to pins 1 and 2, RS485A1 and RS485B1, which Growatt uses for monitoring. Pins 3 and 4 are the energy meter's.

Applies to: MOD 3000-15KTL3-X3 and MOD 17K-33KTL3-X3
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 Growatt MOD TL3-X3

How the dongle recognises it: The dongle reads it as a MOD TL3-X without a battery: the type code 5002, or no type code when the range that answers fits.

GridZeno Dongle for Growatt MOD TL3-X3

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 ferrules for the two wires in the connector.
USB power: A 5 V USB charger and a cable with USB-C.

The port

The round connector marked COM on the underside next to the USB port: to the left of it on the 3-15K and to the right of it on the 17-33K. The same connector is used for the energy meter, so there may already be wires in pins 3 and 4.

Port: COM (4-pin connector)

The COM connector, as Growatt draws it: pins 3 and 4 at the top, 1 and 2 at the bottom. Pins 1 and 2 are for monitoring, pins 3 and 4 for the energy meter. The numbers are on the plug.

Pin 1 A, RS485A1
Pin 2 B, RS485B1

The cable

A network cable with an RJ45 plug for the dongle at one end and the other end cut off. At the inverter end, only the two wires from pins 4 and 5 are used, with ferrules on.

From the dongle to the inverter
Dongle end	Inverter end
Pin 4, blue (A)	COM pin 1, RS485A1
Pin 5, white/blue (B)	COM pin 2, RS485B1
The other wires	Cut off and insulated

Settings

On the inverter

General Setting > Address: 001, as from the factory
Modbus: Modbus RTU at 9600 baud, 8N1. That's what the dongle uses from the factory, so there's nothing to set.

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: Growatt, MOD
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
Press the touch button once to scroll, and twice to select. Go to General Setting, past Language, to Address. It must be set to 001, as from the factory.
2
Unplug the COM connector
Turn off the inverter first: switch off the AC breaker, set the DC switch to OFF, and wait until the LED and the display are off. The round 4-pin connector marked COM is on the underside next to the USB port. Press the latch down, and pull it out. If there's only a dust cover, use the COM connector from the accessory bag.
3
Prepare the cable
Pass the cable through the connector's waterproof cable gland and the threaded sleeve. Strip 10 mm of the two wires from pin 4 (blue) and pin 5 (white/blue), and fit terminals. Insulate the other wires.
4
Insert the wires in pins 1 and 2
Blue (A) goes in pin 1 and white/blue (B) in pin 2, following the numbers on the connector, and tighten the screws. Pins 1 and 2 are at the bottom. Don't touch wires in pins 3 and 4: they belong to the energy meter.
5
Plug the connector back in
Push the threaded sleeve into the connector, and tighten the cable gland. Press the connector into COM until it clicks and sits firmly.
6
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.
7
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.
8
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.
9
Log in, and choose your inverter
Log in to GridZeno. Welcome pairs the dongle with its device ID. Then choose your inverter, Growatt MOD, 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 3 and 4 in COM are the energy meter's connection. They must not be moved or connected to anything else. The USB port is for Growatt's own data logger.

Watch out: on the MOD TL3-X3, monitoring is on pins 1 and 2. On the MOD TL3-X and TL3-X2 with the 16-pin connector, it's on pins 3 and 4.

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

What GridZeno can control on Growatt MOD TL3-X3, and how, is on the page about Growatt MOD TL3-X3. If you're stuck, write to us with the model name.

Source

Ports, pins and menus are from the manufacturer's own manual: Growatt MOD 3-15KTL3-X3 and MOD 17-33KTL3-X3 User Manual (EN, 2026-03), Section 3.1, Appearance, 6.4, Connect the signal cable, 9.3, Address, and 10.1, RS485.