IMPORTANT: Make sure to download the Arduino based PLC boards for Arduino IDE.

Software Configuration:

Once the hardware configuration is done, it's possible to proceed with the software configuration and also its usage. Firstable it's
necessary to include the RS485.h library provided in our boards.

#include <RS485.h>

To check if the RS-485 port is working it is easy to use the serial monitor from the Arduino IDE using the right sentence inside the
setup() function:

Serial.begin(9600); 

Then don’t forget to implement the proper initialization of your communication on the setup() function.

RS485.begin(38400);

NOTE: Check the velocity of transmission between the PLC and the Laptop and from the PLC to the device connected by RS-485.

Example Codes

Basic RS-485 write example (send):

// Include Industrial Shields libraries
#include <RS485.h>

//// IMPORTANT: check switches configuration

////////////////////////////////////////////////////////////////////////////////////////////////////
void setup() {
  // Begin serial port
  Serial.begin(9600);

  // Begin RS485 port
  RS485.begin(38400);
}

////////////////////////////////////////////////////////////////////////////////////////////////////
void loop() {
  // Wait bytes in the serial port
  if (Serial.available()) {
    byte tx = Serial.read();

    // Echo the byte to the serial port again
    Serial.write(tx);

    // And send it to the RS-485 port
    RS485.write(tx);
  }
}

Basic RS-485 read example (receive):

// Include Industrial Shields libraries
#include <RS485.h>

//// IMPORTANT: check switches configuration

////////////////////////////////////////////////////////////////////////////////////////////////////
void setup() {
  // Begin serial port
  Serial.begin(9600);

  // Begin RS485 port
  RS485.begin(38400);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
void loop() {
  // Print received byte when available
  if (RS485.available()) {
    byte rx = RS485.read();

    // Hexadecimal representation
    Serial.print("HEX: ");
    Serial.print(rx, HEX);

    // Decimal representation
    Serial.print(", DEC: ");
    Serial.println(rx, DEC);
  }
}

Basic RS-485 full-duplex example:

* Remember that to test the full duplex with your Ethernet PLC you must connect the A, B (receivers) to the Y, X(transmitters).

// Include Industrial Shields libraries
#include <RS485.h>
//// IMPORTANT: check switches configuration
//// IMPORTANT: Full duplex mode is only available when device supports it
////////////////////////////////////////////////////////////////////////////////////////////////////
void setup() {
  // Begin serial port
  Serial.begin(9600);
  // Begin RS485 port
  RS485.begin(38400, FULLDUPLEX);
}

////////////////////////////////////////////////////////////////////////////////////////////////////
void loop() {
  // Wait bytes from the RS-485
  if (RS485.available()) {
    byte tx = RS485.read();
    // In full-duplex mode it is possible to send and receive data
    // at the same time in a secure way
    RS485.write(tx);
    // Echo the byte to the serial port
    Serial.write(tx);
  }
}