Published January 13, 2021 © GPL3+

Delay timer for faults protection

It is a timer that measures the delay time required for protection before the relay trips

IntermediateFull instructions provided253

Things used in this project

Hardware components

Arduino Nano R3

LDR, 5 Mohm

DFRobot I2C 16x2 Arduino LCD Display Module

Resistor 1k ohm

Jumper wires (generic)

Breadboard (generic)

Story

The project is presents automating a digital timer that basically measures time in milliseconds.

The need for this project : in power system protection lab we use a laboratory panel that simulate faults, and we use a various types of relays for protection and multiple options of TMS (Time multiplier setting) for each relay, and we measure the time for every option we set. Therefore the execution of the experiments would be much easier with an automated timer. In-addition the panel had an old-schooled mechanical timer with analog large scale display, the mentioned timer has stopped working again after repairment.

Therefore we needed a working timer with better efficiency and better display.

How does it work :

For the seek of automation the inputs and the outputs of the timer should be within the panel.

The old timer had four terminals two for start then pause and the other two for the reset, therefore the new timer should be customized with these four terminals.

The start/pause terminals has a voltage difference around 230 V AC for start and around 0 V AC for pause.

Converting this panel output for a suitable Arduino input was challenging.

For the seek of accuracy an extraordinary solution is needed, LDR (Light Dependent Resistor) on the Arduino side and very low power light on the panel side was the most suitable solution.

Code

Untitled file

#include "timer.h"
  #include <Wire.h> 
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);

int x = 0;

Timer timer;

void setup()
{  
  lcd.init();
  lcd.backlight();
  lcd.print("Dr-Ayman Quraan");
  delay(250);
  lcd.setCursor(0,1);  
  lcd.print("Eng.Moh Alawneh");
  delay(1100);
  lcd.clear();
  lcd.begin(16,2);
  lcd.print("Eng. ");
  lcd.setCursor(0,1);
  lcd.print("Ahmad AbuMurad");
  delay(1100);
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Press Test Start ");

   
     // timer.start();
}

void loop()
{
     if (analogRead(A0)>20){
          //start the timer
          if (x == 0) {
            lcd.clear();
            lcd.print("Delay Time Is ");
              timer.start();
              x++;
          }

          
          long m=timer.getElapsedTime();
          
          lcd.setCursor(4,1);
         
          lcd.println(m/1000);
          
          lcd.println(m%1000);
          timer.update();
     }
}

Credits

ahmad-abumurad

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Delay timer for faults protection

Things used in this project

Hardware components

Story

Schematics

un_TjG3L2kC19.png

Code

Untitled file

Credits

ahmad-abumurad

Comments

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Delay timer for faults protection

Delay timer for faults protection

Things used in this project

Hardware components

Story

Schematics

un_TjG3L2kC19.png

Code

Untitled file

Credits

ahmad-abumurad

Comments

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