Growatt/Sungold TL inverters impossible monitoring

[vnk14n]

Hi everyone,

I'm trying to read data from a Growatt 2000 (TL series, firmware G.2.0) inverter installed in 2014, but I can't get any response from the inverter whatsoever.
So far I'm working with an Ubuntu machine connected to the inverter via a RS232-USB cable.

I've tried a couple libraries to use the Modbus protocol but none of them work. I'm referring in particular to the pymodbus package and goburrow/modbus.

I'm configuring the connection in this way:

• Connection: rtu
• Address: /dev/ttyUSB0
• BaudRate: 9600
• DataBits: 8
• Parity: none
• StopBits: 1
• SlaveId: 2
• Timeout: 1s

Where SlaveId is the COM address of the inverter. On this field I've also tried 0, 1.

The cable has 3 leds for: power, transmitting, receiving; only the first two power on.


Essentially when I try to read some registers (e.g. reading holding registers from 0 to 30) the request goes in timeout.
There are several projects on GitHub to read data from Growatt inverters, but the ones I've tried don't (and can't) work since they depend on the same modbus libraries.

--

I've set up a virtual machine with Windows 10, "sharing" the RS232-USB device.
In the machine I've installed ShineBus to see if at least it managed to read some data; no success.
Somewhere I found a working link to a copy of the shameful archaic ShineNET, which doesn't even start.

I also tried with a phisical machine with Windows 7 but I didn't have any success. Getting a response from this inverter seems impossible.

--

Is there something else I can try? Something I'm missing?
I also ran a loopback test on the serial-usb cable and went successful: the cable works.

Thank you very much!

 

[octal_ip]

You seem to be using RS232 when your inverter has an RS485 interface. Grab yourself a USB to RS485 adaptor and try again.

 

[vnk14n]

You seem to be using RS232 when your inverter has an RS485 interface. Grab yourself a USB to RS485 adaptor and try again.

The inverter has both RS232 and RS485. So far any communication via the former has been unsuccessful. Soon I'll try with the latter.

Are you implying that it is generally better to use RS485?

 

[RCinFLA]

Although inverter digital output may be applied to both RS232 and RS485, it is likely the inverter only reads incoming data, including handshakes, from one of the ports. RS485 is likely the default input port.

 

[Solar Guppy]

You also have to be reading supported register address(s), otherwise you get no response.