How can i read and write the data from a Delta plc-s series through Arduino UNO?

Question

I am trying to communicate PLC with arduino through rs232 as well rs 485. But, I am not able to read and write data. I can observe the data in PLC through ladder logic but not in arduino. I am trying to implement the Modbus ASCII here but reading and writing both is not happening.

#include <EmSevenSegment.h>
#include<SoftwareSerial.h>


EmSevenSegment disp(4, 'C', 4, 3, 2);
SoftwareSerial debuggingSerial(0, 1); //RX,TX


[![enter image description here][1]][1]String readlineString = "";
String integerString = "";
String decimalString = "";
String outputString = "";
char startChar = 0x01;
char endChar = 0x01;
//char weight[10];

void setup()   {
  Serial.begin(9600);
  debuggingSerial.begin(9600);

}


void loop() {
  Serial.print("!!!!!!!!!!11111111111\n");
  delay(1000);
  if (debuggingSerial.available())
  {
    Serial.print("!!!!!!!!!!2222222222\n");
    readlineString = debuggingSerial.readString();
    Serial.print(readlineString);
  }

  if (readlineString.length() > 0)
  {
    Serial.print("!!!!!!!!!!333333333333\n");
    integerString = readlineString.substring(10, 12);
    decimalString = readlineString.substring(13, 15);
    int number = (integerString + decimalString).toInt(); // 6789; //Number to be displayed
    disp.print(number); // Print the number
    Serial.print(readlineString);
    readlineString = "";
  }

}

Please find the image of rs232 connection:

Hi, please check the query once again. It is attached now. It is below arduino code. — Mohit Tripathi, Mar 25 '20 at 04:07
what are the rs232 signal names of the pins that you connected? — jsotola, Mar 25 '20 at 04:12
the signal name are Rx(brown wire) and Tx(beside brown wire) and last pin is GND. — Mohit Tripathi, Mar 25 '20 at 04:15
that describes three pins .... the picture shows three wires ... that is six pins .... please answer the question again — jsotola, Mar 25 '20 at 04:22
I am trying to read and write only. I don't think so, we need all the pins for reading and writing using modbus protocol. — Mohit Tripathi, Mar 25 '20 at 04:37
You cannot use software serial on pin D0 and D1. Those two pins are for hardware serial (i.e. for your Serial.println()) — Fahad, Mar 25 '20 at 07:13
it means that I can not read and write the value through these two pins — Mohit Tripathi, Mar 25 '20 at 08:43

How can i read and write the data from a Delta plc-s series through Arduino UNO?

0 Answers0