In this post it will be seen how to read the time since the Arduino based PLC board began running with the function millis(). Basically this function return the number of milliseconds since the controller began running the current program. This function is really useful when you want to control process comparing time
*This value will overflow after 50 days approximately
Function
time = millis();
Parameters
Nothing
Return
Unsigned long of millisecond since the controller program started
Example
Code Example, blinking of an analog outputs:
unsigned long actualtime = 0;
unsigned long beforetime = 0;
unsigned long deltatime = 1000;
bool laststate = true;
void setup() {
Serial.begin(9600);
pinMode(Q0_0, OUTPUT);
}
void loop() {
//Save actual time on actualtime variable
actualtime = millis();
//Compare if it have passed a second
if (actualtime - beforetime >= deltatime){
if (laststate){
//Digital output at HIGH position
digitalWrite(Q0_0, HIGH);
laststate = false;
}
else{
//Digital output at LOW position
digitalWrite(Q0_0, LOW);
laststate = true;
}
//Set beforetime to the actual value of microseconds
beforetime = millis();
}
}
