Hi I’m currently trying to use Arduino to perform serial communication with my Korad Power Supply. I have the code below and all I got was just:

10:28:42.744 -> Sent command: VSET1:5.00 10:28:43.730 -> No response from power supply.

My Arduino was connected to Korad Power Supply with a RS232 TTL Module.enter image description here

I was wondering what could be wrong.

Here is my code:
[enter image description here](https://i.sstatic.net/82wbsvLT.jpg)

#include <SoftwareSerial.h>

#define RX_PIN 10    // RX pin for SoftwareSerial
#define TX_PIN 11    // TX pin for SoftwareSerial
#define TEST_COMMAND "VSET1:5.00" // Test command without line endings

SoftwareSerial mySerial(RX_PIN, TX_PIN); // Create a SoftwareSerial object

void setup() {
  Serial.begin(9600); // Initialize hardware serial for debugging
  mySerial.begin(9600); // Initialize SoftwareSerial

  delay(1000); // Brief delay to ensure everything is ready

  // Send a test command
  sendTestCommand();
}

void loop() {
  // Send the test command periodically
  sendTestCommand();
  delay(5000); // Wait 5 seconds before sending again
}

void sendTestCommand() {
  // Send the command without adding any line endings
  mySerial.print(TEST_COMMAND);
  Serial.println("Sent command: " + String(TEST_COMMAND));

  // Read and display any response
  unsigned long startTime = millis();
  bool responseReceived = false;
  while (millis() - startTime < 1000) { // Wait up to 1 second for response
    if (mySerial.available() > 0) {
      String response = mySerial.readStringUntil('r');
      Serial.println("Power Supply Response: " + response);
      responseReceived = true;
    }
  }

  if (!responseReceived) {
    Serial.println("No response from power supply.");
  }
}