Hello there.
I'm trying to interrupt a delay function. I'm getting nowhere and have tried searching the forums, but am only getting results that indicate not to use delay in and interrupt. I'm looking at the other way round.
The reason I'm trying to do this is for a MIG welder; you set a delay on how long the gas stays on for after the trigger has been released. However the operator must be able to start welding again during this delay period.
I've included all my code below, just in case I've missed something, but the function in spot-light is delay_gas()
the board is an UNO
//definitions & declarations
#define out_WS 3 //Motor speed control pin
#define out_GAS 7 //Gas relay control pin
#define out_CON 8 //Contactor relay control pin
#define out_BRK 4 //Motor brake relay control pin
#define in_WF 12 //Wire Feed button input pin
#define in_DIR 5 //Wire feed direction control input - later version of development
#define out_DIR 6 //Wire feed control output - later version of development
#define INCH_SP 64 //Inch Speed
volatile boolean trig_EN = false; //logical state/flag indicating if trigger has been pressed from interrupt
int WS_MIN = 20; //Minimum wire speed
int WS_MAX = 255; //Maximum wire speed
int GDEL_MIN = 10; //Minimum gas delay time
int GDEL_MAX = 5000; //Maximum Gas Delay time
boolean TTO = true; //This Time Only - for things that only need to happen once during operation
//setup
void setup()
{
pinMode(out_WS, OUTPUT);
pinMode(out_GAS, OUTPUT);
pinMode(out_CON, OUTPUT);
pinMode(out_BRK, OUTPUT);
pinMode(in_WF, INPUT);
pinMode(13, OUTPUT); //LED Alive pin
attachInterrupt(0, trig, FALLING); //attach interupt 0 to function trig, INT0 is on physical pin 2 on Adruino
delay(10);
}
void loop()
{
alive(); //blinks LED on pin 13 REALLY fast
inch(); //check to see if Inch button is pressed
while(trig_EN == true)
{
while(digitalRead(2) == LOW)
{
weld(); //start welding
}
digitalWrite(out_CON, LOW); //turn off current
delay(100); //delay for a little while for a small amount of wire to feed out of lance
digitalWrite(out_BRK, LOW); //apply brake to motor
TTO = true; //reset This Time Only to true - we want gas delay at start of next weld again
trig_EN = false; //reset the trigger flag to false
delay_gas();
digitalWrite(out_GAS, LOW);
}
}
void trig() //function interupt is attached to
{
trig_EN = true;
}
void weld() //controls welding
{
digitalWrite(out_GAS, HIGH); //turn gas on
while(TTO == true)
{
delay(50); //delay to allow gas to flow a bit to form shroud
TTO = false; //change TTO to false so as not to run this dealy again when passing through again
}
feed_wire(); //feed wire
digitalWrite(out_CON, HIGH); //close contactor
}
void inch() //feeds the wire
{
while(digitalRead(in_WF) != HIGH)
{
feed_wire();
}
digitalWrite(out_BRK, LOW); //turn on brake
}
void feed_wire()
{
int i = analogRead(0); //read input of wirefeed speed
int WF_speed = map(i, 0, 1023, WS_MIN, WS_MAX);
digitalWrite(out_BRK, HIGH); //Release Brake on motor
analogWrite(out_WS, WF_speed); //set the output speed of feed motor
}
void delay_gas()
{
int d = analogRead(1);
for(int del = map(d, 0, 1023, GDEL_MIN, GDEL_MAX); del > 1; del--) //still having issue with interupt not cutting into this function
{
delay(1);
}
}
void alive()
{
digitalWrite(13, !digitalRead(13)); //this will cause the LED to appear to stay on, but is blinking rapidly, for diag.
//delay(100) //if required
}
As you can see I read the analog input from a Pot, then in the if statement, I map the variable "d" as "del" against the max and min delays defined at the start. I suppose I could have done:
for(int del = map(analogRead(1), 0, 1023, GDEL_MIN, GDEL_MAX); del > 1; del--)
Anyway, I'm using delay(1); in this for loop in hope that the interrupt will cut in whilst decrementing and checking del. But obviously its not working and when I press the trigger(interrupt) with delay up to max, it doesn't start again till after the delay period.
Could I employ the old way of just performing some long winded maths to waste some time instead? and if so, how long does one subtraction take for the arduino uno?
