Install GridZeno on Growatt MID-HU.
MID-HU is Growatt's large three-phase hybrid inverter with a battery, from 29.9 to 50 kW. The signal ports are in a COM panel with five RJ45 ports and a terminal block under a waterproof cover. The dongle is plugged into Para.out, Growatt's RS485 port for parallel operation, where A is on pin 5 and B on pin 1. The inverter end is crimped with only those two wires.
- Applies to
- MID 29.9K-50K-HU and MID 20-30KTL3-HU-L
- Connection
- Network cable with RJ45 plug
- Time
- About 25 minutes
The battery is controlled with Growatt's VPP protocol: a command with power and duration, which the dongle removes itself when the block ends. What GridZeno can do on Growatt MID-HU
How the dongle recognises it: The type code 5401, which the MID 33-50KTL3-HU has. The dongle reads it with the MOD TL3-XH map and knows it's a MID because you choose MID when you set up GridZeno.
What you need
- GridZeno Dongle
- The device ID is on the label, e.g. GZ-A1B2C3.
- Cable
- A network cable that's re-crimped at the inverter end with only two wires.
- RJ45 plug and crimping tool
- For the inverter end.
- Screwdriver
- Phillips, for the four screws in the waterproof cover over the COM panel.
- USB power
- A 5 V USB charger and a cable with USB-C.
The port
In the COM panel on the underside between the USB port and LOAD, under a waterproof cover with four screws. The ports are in three rows: Para.out and DRMS at the top, Dry contact and BAT in the middle, Para.in and Meter at the bottom.
- Port
- Para.out (RJ45)
- Pin 5 A, 485A
- Pin 1 B, 485B
How it differs from MOD TL3-HU
MID-HU is the larger of the two: MID 29.9K-50K-HU and MID 20-30KTL3-HU-L. MOD TL3-HU covers MOD 3000-15KTL3-HU, that is 3-15 kW.
Both have the type code 5401, so the dongle can't tell them apart by itself. That's why you choose MID when you set up GridZeno.
The port has the same name, Para.out, but on MID-HU the COM panel sits between the USB port and LOAD, with the ports in three rows.
The cable
A network cable where the inverter end is crimped with only two wires: the dongle's A (blue, pin 4) on pin 5 and B (white/blue, pin 5) on pin 1. The other positions in the connector are empty. An ordinary straight cable doesn't work here, because A and B are on pins 5 and 1, not on 4 and 5.
| Dongle end | Inverter end |
|---|---|
| Dongle pin 4, blue (A) | Para.out pin 5, 485A |
| Dongle pin 5, white/blue (B) | Para.out pin 1, 485B |
| 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, 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.
- 1Check 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.
- 2Turn off the inverter, and remove the COM cover
Switch off the AC breaker, set the DC switch to OFF, and switch off the battery's DC switch. Wait 5 minutes. The COM panel is on the underside between the USB port and LOAD. Unscrew the four screws in the waterproof cover.
- 3Crimp the inverter end with two wires
Cut off the connector at the inverter end. Crimp on a new RJ45 connector with blue (A) on pin 5 and white/blue (B) on pin 1. The other wires are cut off and insulated. The other end, for the dongle, keeps its connector.
- 4Pass the cable through the cover
Pass the cable through the waterproof cover and the threaded sleeve, and press it into the rubber ring from the side. Leave the sealing plugs in the holes that aren't used.
- 5Plug the connector into Para.out
Press the plug into the Para.out port at the top left until it clicks. If Para.out is taken by a cable to another inverter, use Para.in at the bottom left, if it's free.
- 6Screw the cover back on
Press the rubber ring into place, screw the four screws in the cover tight, and tighten the threaded sleeve so the COM panel is sealed.
- 7Plug 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.
- 8Connect 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.
- 9Connect 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.
- 10Log 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
What GridZeno can control on Growatt MID-HU, and how, is on the page about Growatt MID-HU. 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-HU & MID TL3-HU-L User Manual (GR-UM-481-A-03, EN, 2025), Figure 3-3, Appearance, 5.7.1, COM port (figure 5-8 and table 5-4), 5.7.2, Connecting the COM connector (figure 5-9), and 6.3, Setting the communication address.