Installation · Growatt

Install GridZeno on Growatt MID TL3-X2.

The newer MID, TL3-X1, TL3-X2 and XL2, are three-phase grid-tied inverters without a battery. They have only one signal connector, the round 16-pin COM connector. The dongle is connected with two wires to pins 3 and 4, RS485A1 and RS485B1, which Growatt uses for monitoring.

Applies to: MID 17-25KTL3-X1, 30-40KTL3-X, 10-20KTL3-XL(1), 6-12KTL3-XL2, 15-25KTL3-XL2 and 17-50KTL3-X2
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 MID TL3-X2

How the dongle recognises it: The dongle reads it as a MID TL3-X: the type code 5001. The XL and XL2 models aren't in the type table and are recognised by the registers that answer.

GridZeno Dongle for Growatt MID TL3-X2

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 just below the USB port, between the PV inputs and AC. The same connector is used for the energy meter and DRM, so there may already be wires in it.

Port: COM (16-pin connector)

The COM connector as Growatt draws it, with the pins counted from right to left in each row. Pins 3 and 4 are for monitoring, pins 7 and 8 for the energy meter. The numbers are on the plug.

Pin 3 A, RS485A1
Pin 4 B, RS485B1
Pin 1 Must not be connected, +12V, dry contact
Pin 2 Must not be connected, COM, dry contact

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 3, RS485A1
Pin 5, white/blue (B)	COM pin 4, RS485B1
The other wires	Cut off and insulated

Settings

On the inverter

Set parameter > General > Set Command: 1, as set at 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, MID
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
Tap the touch button once to scroll, and twice to select. Go to Set parameter and General, past Set Language and AUTO TEST, to Set Command. It must be 1, as set at the factory.
2
Unplug the COM connector
Switch the inverter off first: switch off the AC breaker, and set the DC switch to OFF. The round 16-pin connector marked COM is on the underside just below the USB port. Press the lock down, and pull it out, preferably with the H-shaped removal tool from the accessory bag. 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 cover 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
Put the wires in pins 3 and 4
Blue (A) goes in pin 3 and white/blue (B) in pin 4, by the numbers on the connector, and tighten the screws. Pins 1, 2 and 3 are in the top row, counted from the right. Pins 1 and 2 supply 12 V to a relay, and pins 7 and 8 are the energy meter's: don't touch them.
5
Plug the connector back in
Push the threaded sleeve into the connector, and tighten the waterproof cover. 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 MID, 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 1 and 2 in COM supply 12 V to an external relay. Never connect anything from the dongle to them.

Pins 7 and 8 are the energy meter's connection, pins 5 and 6 are set aside for a battery, and pins 9 to 14 are DRM. They must not be moved or connected to anything else. The USB port is for Growatt's own data logger.

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

What GridZeno can control on Growatt MID TL3-X2, and how, is on the page about Growatt MID TL3-X2. If you're stuck, write to us with the model name.

Source

Ports, pins and menus are from the manufacturer's own manual: Growatt MID 10-40KTL3-X (GR-UM-249-A-07), MID 20-30KTL3-X2 (GR-UM-253-A-01) and MID 33-50KTL3-X2 (GR-UM-247-A-01) User Manual, Sections 3.1, Appearance, 6.4, Connect the signal cable, 9.3, Set COM address, and 10.1, RS485.