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When is the function delay() a delay?

colporteur 

else if (MainDepartureState == LOW && MainArrivalState == LOW) {
        if (startupMain == HIGH) {
          // pulse turnout for Main train
          digitalWrite(Main_Turnout, HIGH);
          relayDelay();//<-----1
          digitalWrite(Main_Turnout, LOW);
          if (deBug == HIGH) {
            Serial.println("The Main Turnout Activated");
          }
          // Engage Motor for Main
          motors.setSpeedB(minSpeedB);  // Start Motor for Main
          motors.forwardB();
          PowerMain = LOW;
          startupMain = LOW;
          delay(300000);//<----2
          if (deBug == HIGH) {
            Serial.println("Motor Delay Complete");
          }

According to what I have read “The delay() function allows you to pause the execution of your Arduino code for a specified period.”

Why are the delays I am using not working or the values are so extreme? How can I best accomplish a delay?

I tried using the delay() function at point <----1 in my code and it failed miserably. I wanted to activate a relay by turning it on, waiting for relay to engage (delay(2000), then turn it off. The delay(2000) two seconds didn’t work. I wrote a little relay routine that accomplish what I wanted but why did delay(2000) not give me two seconds?

I am using delay() function at <----2 in the code but the value doesn’t reflect the actual delay. I needed to generate some wait time for the motor to engage and trigger a sensor. My desire was a three second delay(3000) but the delay(300000) was a value that actually worked. That would be 300 seconds yes/no?

I'm a code resurrectionist and not an actual programmer. I will try and muddle through discussions 

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  • I would start by putting a serial.println before and after the delay just to make sure there’s no question of it being the right delay line you’re looking at.

     Also make sure you have selected the correct board for your sketch. There’s a good chance delay() just counts clock cycles, so a faster chip might whip through them faster than a standard old Uno might.

  • in reply to ntewinkel

    That was my low tech way to confirm the code was actually running.

    I drop these lines of code in to use serial print

        if (deBug == HIGH) {  //tell status
      Serial.println("Mark");
    }

    By setting deBug variable I can make the serail print disappear to reduce any impact to the code operation when in production.

    The delay() is not the three seconds I hoped for when I bookend it with the serial print lines.

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  • in reply to ntewinkel

    That was my low tech way to confirm the code was actually running.

    I drop these lines of code in to use serial print

        if (deBug == HIGH) {  //tell status
      Serial.println("Mark");
    }

    By setting deBug variable I can make the serail print disappear to reduce any impact to the code operation when in production.

    The delay() is not the three seconds I hoped for when I bookend it with the serial print lines.

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  • in reply to colporteur

    I don't think you've mentioned yet (unless I missed it) which board you are using?

    The delay() function seems to use SysTick, which I think is (or is related to) the CPU speed, so if in the Arduino IDE something is selected wrong, that might just mess things up.

  • in reply to ntewinkel

    Actually, the clock speed/board setting is easily tested by using the Blink example - if that works fine, then you can rule out board related settings.

    ie, if Blink works properly, then it's something in your code. You could then try testing chunks of your code in a separate test app, to narrow down where that issue might be. I often start small and then add back in bits at a time until it breaks again.