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UART

Juan Tomasetti 3 years ago in Devices / Modbus • updated by Andrew Watson 3 years ago • 7

Hello.

I have a Grinder module, and I would like to connect a Solar Inverter via UART. In the Grinder module, I have connected the CP2102 adapter to the USB port, bOs recognizes it perfectly in the COM3 port. According to the solar inverter documentation, the communication is UART, 115200bps, 8bits data, 1 stop bit, no parity. The COM3 port, so I have configured it. But I can't get a response from the inverter. I have tried all the combinations on the bos, but I cannot receive data. Any suggestion???

Thanks...

Andrew Watson 3 years ago

Hi

If bOS sees the CP2102 as COM3 then it is working correctly as far as the underlying Windows 10 operating system is concerned. However, I see that you have posted this in the Modbus section, and if your inverter is like my SMA unit it requires an RS485 UART to communicate with your Grinder on Modbus. The CP2102 is an RS232 UART and this will not work.

Andy

Juan Tomasetti 3 years ago

Hello.
The inverter that I have installed has RS485 and RS232 communication. RS485 is only used for communication with the power meter, so I can only get data through RS232. bOS can't work by RS232???
Thanks.

Andrew Watson 3 years ago

Hi

The bOS "Basic" device certainly works - there are lots of users and a section in this forum dedicated to it. To check out your RS232 communications I'd recommend using a terminal emulator programme such as Putty or Teraterm - both reputable free downloads. You need to login to Windows and you can then connect directly to your solar inverter and see if it communicates as expected before trying to use bOS. You'll need to check the supplier's documentation to see if there are any special sequences needed to start communications and whether it's binary or ASCII data.

Andy

Juan Tomasetti 3 years ago

Hello again.

I am very sorry for my clumsiness, but I am unable to receive data from the Inverter. I have tried both the Serial connection and the TCP connection in Basic Device. They both connect. Surely I do something wrong. Can someone provide an example of how to implement it?

I include the command protocol.

Thanks.

Andrew Watson 3 years ago

Juan

Can you confirm that you have successfully communicated using Terraterm or Putty? If that doesn't work then bOS won't. 


I assume that you inverter is manufactured by SAJ. can you please post a link to the product manual and to the full protocol manual, including the hardware interface connection. It's really hard to work out what is going on without all the information.

Here's how I would start setting up the Basic driver

 

But your protocol has a CRC and I have no idea to calculate this and bOS cannot do this for arbitrary hex strings. You could precalculate for specific commands.

Andy

Juan Tomasetti 3 years ago

Hello again.

The communication exists. Attached protocol and RS232 port connections.GH-IH Style Modbus Communication Protocol (2).pdf

Andrew Watson 3 years ago

Juan

Thanks for the link and the diagram. I'm afraid that none of it makes any sense. There is no information on calculating the CRC-16 so you can't create and send valid data packets. See this https://crccalc.com/ for CRC-16. The hardware diagram also doesn't look correct either - the top diagram says "USB" and the socket looks like a USB with 4 pins but the table claims that it is 9 pin RS232. I'm sorry but I don't think I can help you any further. I suggest that you contact the supplier / manufacturer directly and ask them how you can communicate using RS232.

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