Installation · Sofar Solar

Install GridZeno on Sofar 250-350 kW, 800 V.

Sofar's largest grid inverters for solar parks are connected to an 800 V grid behind a transformer. They have the same 16-pin COM connector as the smaller KTLX. The dongle is connected with three wires: A in pin 1, B in pin 3 and GND in pin 7.

Applies to: 250/255KTL-HV, -HV-PRO, 255KTL-HV-TRO and 250-350KTLX0/X1
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 250-350 kW, 800 V

How the dongle recognises it: The serial number in holding 0x0445 with the code R1: 255KTL-HV.

GridZeno Dongle for Sofar 250-350 kW, 800 V

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: Three wire ferrules.
USB power: A 5 V USB charger and a cable with USB-C.

The port

On the underside of the inverter, by the USB port. The same connector is used for DRM, so there may already be wires in it.

Port: COM (16-pin connector, RS485 Modbus/DRMs)

The COM connector, as Sofar numbers the pins. Pins 1 and 2 are A, pins 3 and 4 are B, and pins 7 and 13 are GND.S. The numbers are on the plug.

Pin 1 A, RS485 A
Pin 3 B, RS485 B
Pin 7 GND, GND.S
Pin 8 Must not be connected, DRM0

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 three wires from pins 4, 5 and 3 are used, with terminals on.

From the dongle to the inverter
Dongle end	Inverter end
Dongle pin 4, blue (A)	COM pin 1, RS485 A
Dongle pin 5, white/blue (B)	COM pin 3, RS485 B
Dongle pin 3, white/green (GND)	COM pin 7, GND.S
The other wires	Cut off and insulated

Settings

On the inverter

Enter Setting > 7. Set Address and 18. Baud rate setting: The address is 01 from the factory. Read the baud rate: the dongle must have the same. 250-350KTLX0/X1 has no display, so it's set in the SofarCloud app over Bluetooth.

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, KTL-HV
Connection: By cable (RS485)
RS485 settings: Same baud rate and address as the inverter, 8N1. Start with 9600 and 1 if you can't find them.

Step by step

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

1
Read off the address and baud rate
On the display, go to Enter Setting. The address is under 7. Set Address, 01 from the factory, and the baud rate under 18. Baud rate setting. Note them down: the dongle must have the same. On 250-350KTLX0/X1 they're in the SofarCloud app.
2
Switch off, and take out the COM connector
Stop the inverter first from the display or the app, and check that it delivers 0 W. Then switch off the AC breaker and then the DC switches. Wait 5 minutes after the display has gone off, on 250-350KTLX0/X1 25 minutes. Take out the COM connector.
3
Pass the cable through the connector's parts
Pass the cut end of the cable through the connector's nut and seal before the wires are put in.
4
Prepare the cable
Strip 20 to 25 mm of the outer sheath and 12 to 15 mm of the three wires from pin 4 (blue), pin 5 (white/blue) and pin 3 (white/green), and put terminals on. Insulate the other wires.
5
Put the wires in pins 1, 3 and 7
Blue (A) goes in pin 1, white/blue (B) in pin 3 and white/green (GND) in pin 7, following the numbers on the connector. Push them in until they click.
6
Plug the connector back in
Plug the connector into the COM port 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 KTL-HV, and the connection By cable (RS485). Set the inverter's baud rate and address under RS485 settings. 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

The inverters are on an 800 V grid. The work must be done by an authorised installer, and the AC and DC switches must not be opened under load.

Pins 5 and 6 are the energy meter's connection and pins 8 to 12 the DRM control, where pin 8 can stop the inverter. Don't touch them.

If the park uses Sofar's PLC or a communication box (PSC), it's already master on RS485. Write to us before you connect the dongle.

What GridZeno can control on Sofar 250-350 kW, 800 V, and how, is on the page about Sofar 250-350 kW, 800 V. If you're stuck, write to us with the model name.

Source

Ports, pins and menus are from the manufacturer's own manual: SOFAR 250-255KTL-HV, 250-255KTL-HV-PRO, 255KTL-HV-TRO and 250-350KTLX0 User Manuals (EN), The pin table for the COM plug (RS485 Modbus/DRMs), Enter Setting (7. Set Address and 18. Baud rate setting) and shutdown.