nRF9160 RS485 MODBUS

[Netanel]

Hello, 

I would like to know if the nRF9160 supports RS485 MODBUS Communication protocol ?

[ovrebekk]

Hi 

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

[Netanel]

Hello Torbjorn, 

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

[Adeel]

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.

[ovrebekk]

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

[Adeel]

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. 

[ovrebekk]

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

[Adeel]

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.

[ovrebekk]

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

[Adeel]

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.

[ovrebekk]

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

[yugesh]

Adeel said:

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.

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

[Adeel]

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.