Arduino-Nextion communication does not works after implementing an RS485 Bridge

Projects Networking, Protocols, and Devices
1

Hello,

I have a problem at hand that I can only share a schematic and not the code due to my industries requirements. Normally we were working with and Arduino Due and a 7' Nextion screen where TX and RX were connected directly. Now we have implemented an RS485 bridge to be able to prolong the distance to over 100 meters.
Both the arduino and nextion communicate @115200
Before adding the bridge their was no problem and now they just dont communicate. I would appreciate even suggestion on what to look for when dealing with this type of problems.
Untitled Diagram.drawio
110000045245442

2

Your board diagram shows the TXD pin is used to accept TX Data from the micro and RXD is the data coming from the RS485 bus.

If that is the case, then why cross the signals on the Nextion side?

Perhaps you need to discover what RX and TX mean on each end?

3

Hello,

I have tried what you have said and got the same exact outcome. I was thinking in this way: when we are wiring an arduino and a nextion we do such as " Arduino TX->Nextion RX and Arduino RX->NExtion TX somewhere on the diagram must be a crossed wiring". I guess I was wrong but still have the same issue, thanks for the quick reply though !

4

Is your RS485 board the same as the one in the picture? The picture shows an auto switching board. Most boards require the additional signals RE & DE to control the transceiver.

5

Why do you need RS485 here at all? Why not to connect Nextion directly trough UART rx, tx?

6

Check if the wires are correctly connected to the RS485 transceiver or converter and that there are no loose connections.

7

Just another thought - you do know that the RS485 setup you have is half duplex - i.e. both devices can't talk at the same time.

8

Yes, it is the same board, I have posted the picture intentionally

9

Because the distance is over 100 meters and rx and tx signals on their own start to get noisy after traveling more than 50 meters.

10

Hi thanks for pointing it out, I have checked the wiring many times even changing them a bit to see if I forgot anything but ended up just wiring like what I did at the start. I double checked but will do once again just to be sure

11

Yes I do know, do you think that I might code a master-slave relationship to be able to deal with this problem ? Because it is automatic with this RS485 module I thought that they could deal with this kind of problems internally, but I might be wrong...

12

You would have to consult the nextion docs to see what they say. You could implement a full duplex RS485 link. You just need 2 more of those transceivers. Google full duplex RS485 for examples.

13

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.