nRF9160 RS485 MODBUS

RE: nRF9160 RS485 MODBUS

Waqar Ahmed — Fri, 19 Aug 2022 10:37:48 GMT

Hi Adeel,
I am trying to setup modbus(RS485) comm using Zephyr modbus example in v1.9.0.

But i am getting timeout error.

i raised the following ticket

Modbus(RS485) communication using UART1 on Nrf9160
Please suggest

RE: nRF9160 RS485 MODBUS

yugesh — Wed, 03 Feb 2021 01:22:14 GMT

Hi Adeel,

Thank you so much for your information :).

Regards,

yugesh

RE: nRF9160 RS485 MODBUS

Adeel — Tue, 02 Feb 2021 10:21:24 GMT

Hi Yugesh,

You can get started with this Github project that includes liblightmodbus sample : https://github.com/linumiz/zephyr/tree/liblightmodbus

It has been configured to be used with Zephyr. So you can work around with this :) .

Regards,

Adeel.

RE: nRF9160 RS485 MODBUS

yugesh — Tue, 02 Feb 2021 07:57:34 GMT

[quote userid="92259" url="~/f/nordic-q-a/53843/nrf9160-rs485-modbus/278733#278733"]

Hi Tobjorn,

Just wanted to let you know that this library can be used and is compatible with Zephyr.

http://jacajack.github.io/liblightmodbus/master_8h.html#afbcff357011e2f7c2eb0469ef80e0d7d

I worked around with it and got it working :). So, if anyone needs any info to start over with modbus, you can suggest this alternative.

Regards,

Adeel.

[/quote]

Hi Adeel,

Could you please let me know how did you work around the liblightmodbus library to work with. It would be very helpful.

Best regards

yugesh

RE: nRF9160 RS485 MODBUS

ovrebekk — Mon, 09 Nov 2020 10:13:16 GMT

Hi Adeel

That is excellent news, thanks for sharing your findings 🙂

Feel free to verify your answer, then it is easier to see that the case is resolved if someone with a similar issue discovers it.

Best regards
Torbjørn

RE: nRF9160 RS485 MODBUS

Adeel — Fri, 06 Nov 2020 09:00:01 GMT

Hi Tobjorn,

Just wanted to let you know that this library can be used and is compatible with Zephyr.

http://jacajack.github.io/liblightmodbus/master_8h.html#afbcff357011e2f7c2eb0469ef80e0d7d

I worked around with it and got it working :). So, if anyone needs any info to start over with modbus, you can suggest this alternative.

Regards,

Adeel.

RE: nRF9160 RS485 MODBUS

ovrebekk — Fri, 25 Sep 2020 07:04:16 GMT

Hi Adeel

I did some asking around, but I couldn't find anyone that has experience with this library unfortunately.

That said it should be relatively easy to integrate if it supports Zephyr and the Zephyr driver model.

The best of luck 🙂

Best regards
Torbjørn

RE: nRF9160 RS485 MODBUS

Adeel — Wed, 23 Sep 2020 13:13:23 GMT

Hi Tobjorn.

Haha, That is true while porting codes and that is why I was looking around for some libraries:).

While looking around for other options, I found one open source Library for Modbus RTU (liblightmodbus) that is compatible with Zephyr.

https://github.com/linumiz/liblightmodbus

Maybe this could be an option to try out as well. It would be too much of an ask but could you enquire with any of your team members whether they have used this library.

In any case, I will try to go ahead and work around with this and will update if I get any success :).

Regards,

Adeel.

RE: nRF9160 RS485 MODBUS

ovrebekk — Wed, 23 Sep 2020 12:21:51 GMT

Hi Adeel

In theory you can do that, yes, but any code interfacing to hardware peripherals (such as timers or the UART) will have to be changed.

How much work this is is hard to say. You usually get an idea when you port the code over and try to compile it, based on the number of errors that pop up ;)

Best regards
Torbjørn

RE: nRF9160 RS485 MODBUS

Adeel — Tue, 22 Sep 2020 13:17:31 GMT

Hi Tobjorn,

Thanks for the update. So, Could I use an external Modbus library file from Arduino to develop on the software side ? How compatible is it to use the external libraries for the internal nRF development applications ?

Regards,

Adeel.

RE: nRF9160 RS485 MODBUS

ovrebekk — Tue, 22 Sep 2020 09:42:43 GMT

Hi Adeel

Nothing has really changed on our side, no, in terms of adding a modbus example for the nRF9160.

Using an RS-485 to UART converter is likely to be the most reliable and easy to implement solution, yes.

Best regards
Torbjørn

RE: nRF9160 RS485 MODBUS

Adeel — Mon, 21 Sep 2020 15:38:24 GMT

Hi Tobjorn.

Would you still advice using an external driver chip to convert from RS-485 to UART and use the UART_0 pins to read the modbus data in the nrf9160 ?

Regards,

Adeel.

RE: nRF9160 RS485 MODBUS

Adeel — Mon, 21 Sep 2020 08:22:49 GMT

Hi Tobjorn,

Any update now on any example program for the Modbus communication devices as I am looking to interface a modbus communication device with the nrf9160DK.

Regards,

Adeel.

RE: nRF9160 RS485 MODBUS

ovrebekk — Thu, 07 Nov 2019 11:31:54 GMT

Hi Netanel

Those settings should work fine.

I can't give you a 100% guarantee that the RS485 device will work with the nRF9160 since it hasn't been tested by us, but I can't see any reason why it shouldn't.

Best regards
Torbjørn

RE: nRF9160 RS485 MODBUS

Netanel — Tue, 05 Nov 2019 15:20:46 GMT

Hello Torbjorn,

The Baud rate is 9600.

RS-485, 9600, 8N1

RE: nRF9160 RS485 MODBUS

ovrebekk — Mon, 04 Nov 2019 13:53:19 GMT

Hi Netanel

Yes, the Modbus RTU protocol would basically have to be implemented in software, as the UART module doesn't handle modbus, and this we don't provide any examples for.

I will need some more time to investigate if we have tested the modbus protocol to make sure our UART is compatible, but as long as you don't have to use odd parity bit (we support even or no parity only), and want to use a baudrate that we support, it should work fine.

Do you know what baudrate you are planning to use?

Best regards
Torbjørn

RE: nRF9160 RS485 MODBUS

Netanel — Fri, 01 Nov 2019 11:27:05 GMT

Hello Torbjorn,

I would like to connect sensors via RS485 to the nrf9160.

Temperature, pressure, flow, etc.

regarding the software side, I mean do I need any driver running on the nrf9160 to collect the data from RS485 and send it to the cloud ? Using MODBUS RTU .

RE: nRF9160 RS485 MODBUS

ovrebekk — Fri, 01 Nov 2019 10:11:51 GMT

Hi Netanel

Like I mentioned in your other case the STR485 should work fine if you can set the UART interface correctly.

What kind of device(s) are you talking to over the bus?
Nordic devices also, or some other type of device?

When you say software side, are you thinking about the driver for the STR485?

Best regards
Torbjørn

RE: nRF9160 RS485 MODBUS

Netanel — Thu, 31 Oct 2019 12:13:09 GMT

Hello Torbjorn,

would the STR485 be suitable? What about the software side ?

RE: nRF9160 RS485 MODBUS

ovrebekk — Thu, 31 Oct 2019 12:02:51 GMT

The nRF9160 does not have RS485 support, no.

You would need some kind of driver chip to convert from UART to RS485.

Best regards
Torbjørn