Talking to a device via serial using Arduino Nano

Projects General Guidance
1

Hello,

So I have this proprietary board that measures some external parameters. This board connects to a PC that runs a Windows application, the connection is made via USB - it's actually an USB to serial converter (FTDI RS232 to USB).

The application that i'm using to connect and talk to this hardware is using the following serial params:

  • BAUD: 19200
  • Parity: None
  • Read/Write timeout: 500 ms
  • DTR Enable: True

What I want to accomplish using my Arduino Nano board:

I want to communicate with this proprietary board, I first removed the FTDI convertor from my custom board, then I've connected the RX/TX pins (proprietary board) to TX/RX pins (Nano), and also 5V and Ground.

When I'm sending the command used to initiate communication, nothing happens. I should receive "OK" - ASCII.

I'm confused.
I'm not sure if this can work without that RS232 to serial converter. Shouldn't my Arduino board also connect to some kind of serial converter - and not directly send data to the board?

Any ideas and opinions are welcomed!

2

Me too. No code, no schematics posted.

3

it looks like your target board uses RS232 which uses -12 to +12 volt logic
to connect this to an arduino which uses 5v logic you require an RS232 shield

4

Here's a visualization of my problem:

Untitled Diagram.drawio (1)
Untitled Diagram.drawio (1)807×597 42.3 KB

Here's a basic serial example I am using to test the communication:

#include <SoftwareSerial.h>

SoftwareSerial ELevelBoard(8, 9);     // RX, TX

void setup() {
  // Initialize the serial port for communication with the computer
  Serial.begin(19200);
  Board.begin(19200);
}

void loop() {

  if (Board.available()) {
    char data = Board.read();
    Serial.print(data);
  }

  // Check if data is available on the computer
  if (Serial.available()) {
    char data = Serial.read();
    Board.print(data);
  }
}
6

what arduino board are you using?
which particular FTDI cable did you use to connect to the PC?
how was it connected to the target board?
photos may help

7

Can you share the document that outlines what you can say to and what you can expect to hear from the device?

Can you try just using PuTTY or CoolTerm, just do you can type directly at the device and listen to it, no code, no Arduino?

And where in the code you posted is it making the software serial port be the one that board is using?

a7

8

Shouldn't these 'match up' ?

9

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