If Statements

Using Arduino Programming Questions
1

In my code I have two variables, StationOCC and Lift OCC that are Boolean and can either be true or false. I have a statement such as:

if (StationOCC == true && LiftOCC == false){
digitalWrite(DispatchLT, HIGH);}

The problem is, it writes the DispatchLT high even when the conditions of the if statement aren't valid. For example, if I have it set StationOCC false and LiftOCC true earlier in the code, it still lights up the dispatch light when it gets to this section. What am I doing wrong here?

I'm also having the same issue if I have it read a pin value like:

if (DispatchVAL == LOW && StationOCC == true){
digitalWrite(MotorPin, HIGH);}

In this case, it would allow the MotorPin to be high regardless of what the StationOCC variable is and only look at what the dispatch button value is.

2

Please post your complete code as the snippets do not reveal the cause.

3

I'd be inclined to use Serial to write the values of variables to the monitor at key points, and to print "here I am" from various parts of the code when there are ifs, just to verify where it got to

4

Alright, that's a good idea because maybe it doesn't have the values I think it does.

I can post my whole code but its very long. If that would help though I can do that once I get back home.

5

because maybe it doesn't have the values I think it does.

:wink:

6 
//-----LIGHT PINS-----
const int BlockLT = 2;
const int EstopLT = 22;
const int ResetLT = 23;
const int StationLT = 24;
const int LiftLT = 25;
const int WaitLT = 26;
const int LstopLT = 27;
const int ReintLT = 28;
const int DispatchLT = 29;
//-----BUTTON PINS-----
const int EstopBT = 30;
const int ResetBT = 31;
const int ModeBT = 32;
const int LstopBT = 33;
const int ReintBT = 34;
const int JogBT = 35;
const int DispatchBT = 36;
//-----MOTOR PINS-----
const int LiftMotor = 52;
const int StationMotor = A15;
const int BlockMotor = 50;
const int WaitMotor = 51;
//------PHOTOEYE PINS-----
const int LiftEye = A0;
const int BlockEye = A1;
const int WaitEye = A2;
const int StationEye = A3;
//-----BRAKE PINS-----
const int LWaitBrake = 49;
const int RWaitBrake = 47;
const int StationBrake = 53;
//-----ALL ZONES OCCUPIED-----
boolean StationOCC = true;
boolean LiftOCC = true;
boolean BlockOCC = true;
boolean WaitOCC = true;
//-----VARIABLES-----
boolean ReintPRO = false; //Begin Initalizing Process
boolean CascadePRO;
boolean EstopPRO = false; //Estop Active When 'true'
boolean LstopPRO = false; //Lstop Active When 'true'
boolean DispatchPRO = false;
int EstopLIT = LOW;
int LstopLIT = LOW;
int DispatchLIT;
//-----TIMERS-----
long previousMillis = 0;
long EstopInterval = 250;
long LstopInterval = 250;
long DispatchInterval = 750;

void setup(){
//-----LIGHT PIN SETUP-----  
  pinMode(BlockLT, OUTPUT);
  pinMode(EstopLT, OUTPUT);
  pinMode(ResetLT, OUTPUT);
  pinMode(StationLT, OUTPUT);
  pinMode(LiftLT, OUTPUT);
  pinMode(WaitLT, OUTPUT);
  pinMode(LstopLT, OUTPUT);
  pinMode(ReintLT, OUTPUT);
  pinMode(DispatchLT, OUTPUT);
//-----BUTTON PIN SETUP-----
  pinMode(EstopBT, INPUT_PULLUP);
  pinMode(ResetBT, INPUT_PULLUP);
  pinMode(ModeBT, INPUT_PULLUP);
  pinMode(LstopBT, INPUT_PULLUP);
  pinMode(ReintBT, INPUT_PULLUP);
  pinMode(JogBT, INPUT_PULLUP);
  pinMode(DispatchBT, INPUT_PULLUP);
//-----MOTOR PIN SETUP-----
  pinMode(LiftMotor, OUTPUT);
  pinMode(StationMotor, OUTPUT);
  pinMode(BlockMotor, OUTPUT);
  pinMode(WaitMotor, OUTPUT);
//-----PHOTOEYE PIN SETUP-----
  pinMode(LiftEye, INPUT);
  pinMode(BlockEye, INPUT);
  pinMode(WaitEye, INPUT);
  pinMode(StationEye, INPUT);
//-----BRAKE PIN SETUP-----
  pinMode(LWaitBrake, OUTPUT);
  pinMode(RWaitBrake, OUTPUT);
  pinMode(StationBrake, OUTPUT);
}

void loop(){
  //Starting Millis Timer
  unsigned long currentMillis = millis();
  //Reading Button Values
  int EstopVAL = digitalRead(EstopBT);
  int DispatchVAL = digitalRead(DispatchBT);
  int ReintVAL = digitalRead(ReintBT);
  int LstopVAL = digitalRead(LstopBT);
  int JogVAL = digitalRead(JogBT);
  int ResetVAL = digitalRead(ResetBT);
  int StationEyeVAL = digitalRead(StationEye);
  int LiftEyeVAL = digitalRead(LiftEye);
  int BlockEyeVAL = digitalRead(BlockEye);
  int WaitEyeVAL = digitalRead(WaitEye);
  int ModeVAL = digitalRead(ModeBT);
  

//-----SYSTEM IN MAINT MODE-----
if (ModeVAL == HIGH){    
  //Use Dispatch Button to Test Block Motor
  if (DispatchVAL == LOW){
    digitalWrite(BlockMotor, HIGH);}
  else{
    digitalWrite(BlockMotor, LOW);}
    
  //Use Initalize Button to Test Station Motor
  if (ReintVAL == LOW){
    digitalWrite(StationMotor, HIGH);}
  else{
    digitalWrite(StationMotor, LOW);}
    
  //Use Reset Button to Test Station Brake
  if (ResetVAL == LOW){
    digitalWrite(ResetLT, HIGH);
    digitalWrite(StationBrake, HIGH);}
  else{
    digitalWrite(ResetLT, LOW);
    digitalWrite(StationBrake, LOW);}
    
  //Use LiftStop Button to Test Lift Motor  
  if (LstopVAL == LOW){
    digitalWrite(LstopLT, HIGH);
    digitalWrite(LiftMotor, LOW);}   
   else{
    digitalWrite(LstopLT, LOW);
    digitalWrite(LiftMotor, HIGH);}
    
  //Photoeye at Station Test
  if (StationEyeVAL == LOW){
    digitalWrite(StationLT, HIGH);}
  else{
    digitalWrite(StationLT, LOW);}
    
  //Photoeye at Lift Test
  if (LiftEyeVAL == LOW){
    digitalWrite(LiftLT, HIGH);}
  else{
    digitalWrite(LiftLT, LOW);}
  
  //Photoeye at Block Test
  if (BlockEyeVAL == LOW){
    digitalWrite(BlockLT, HIGH);}
  else{
    digitalWrite(BlockLT, LOW);}
    
  //Photoeye at Wait Test
  if (WaitEyeVAL == LOW){
    digitalWrite(WaitLT, HIGH);}
  else{
    digitalWrite(WaitLT, LOW);}  
    
  //Wait Brake Test
  if (JogVAL == LOW){
    digitalWrite(RWaitBrake, HIGH);
    digitalWrite(LWaitBrake, HIGH);
    digitalWrite(EstopLT, HIGH);}  
  else{
    digitalWrite(LWaitBrake, LOW);
    digitalWrite(RWaitBrake, LOW);
    digitalWrite(EstopLT, LOW);}
  if (JogVAL == HIGH && WaitEyeVAL == LOW){
    digitalWrite(WaitMotor, HIGH);
    delay(1200);}
  else{
    digitalWrite(WaitMotor, LOW);} 
}
//-----SYSTEM IN AUTO MODE-----
else{
//-----*****EMERGENCY STOP MODE*****-----
if (EstopVAL == LOW){
  EstopPRO = true;}
if (EstopPRO == true){
  digitalWrite(LiftMotor, LOW);
  digitalWrite(BlockMotor, LOW);
  digitalWrite(WaitMotor, LOW);
  digitalWrite(StationMotor, LOW);
  digitalWrite(RWaitBrake, HIGH);
  digitalWrite(LWaitBrake, HIGH);
  digitalWrite(StationBrake, HIGH);
  digitalWrite(LstopLT, HIGH);
    if(currentMillis - previousMillis > EstopInterval){//Estop Blinking
    previousMillis = currentMillis;
      if (EstopLIT == LOW){
        EstopLIT = HIGH;}
      else{
        EstopLIT = LOW;}
      digitalWrite(EstopLT, EstopLIT);}}
//-----*****LIFT STOP MODE*****-----
if (LstopVAL == LOW){
  LstopPRO = true;}
if (LstopPRO == true){
  digitalWrite(LiftMotor, LOW);
    if(currentMillis - previousMillis > LstopInterval){//Lift Stop Blinking
    previousMillis = currentMillis;
      if (LstopLIT == LOW){
        LstopLIT = HIGH;}
      else{
        LstopLIT = LOW;}
      digitalWrite(LstopLT, LstopLIT);}}
//-----*****FAULT RESETING*****-----
if (EstopPRO == true && EstopVAL == HIGH){
  digitalWrite(ResetLT, HIGH);}
if (LstopPRO == true && LstopVAL == HIGH){
  digitalWrite(ResetLT, HIGH);}
if (ResetVAL == LOW && EstopVAL == HIGH && LstopVAL == HIGH){
  EstopPRO = false;
  LstopPRO = false;
  digitalWrite(EstopLT, LOW);
  digitalWrite(LstopLT, LOW);
  digitalWrite(ResetLT, LOW);}
  
//Indicates initalization needs to be performed when all blocks are occupied  
  if (StationOCC == true && LiftOCC == true && BlockOCC == true && WaitOCC == true){
    digitalWrite(ReintLT, HIGH);}
//Occupied lights on when zone is occupied  
  if (StationOCC == true){
    digitalWrite(StationLT, HIGH);}
  if (LiftOCC == true){
   digitalWrite(LiftLT, HIGH);}
  if (BlockOCC == true){
   digitalWrite(BlockLT, HIGH);}
  if (WaitOCC == true){
   digitalWrite(WaitLT, HIGH);}

//-----*****DISPATCHING FROM STATION*****-----
//-----*****TRAIN IN LIFT ZONE*****-----
//-----*****TRAIN IN BLOCK ZONE*****-----
if(BlockEyeVAL == LOW && EstopPRO == false && WaitOCC == false){
  digitalWrite(BlockMotor, HIGH);}
else{
  digitalWrite(BlockMotor, LOW);}
//-----*****TRAIN IN HOLD ZONE*****------
} 

}

Here is my code. The area where I am having an issue is at the end.

7

This is where excess brackets can really help.

Try the following and report back:

if ((StationOCC == true) && (LiftOCC == false)){
digitalWrite(DispatchLT, HIGH);}
8

Edit: Nevermind

9

Not really part of the problem, but make these unsigned long
long previousMillis = 0;
long EstopInterval = 250;
long LstopInterval = 250;
long DispatchInterval = 750;

these are all used as digital inputs:
pinMode(LiftEye, INPUT);
pinMode(BlockEye, INPUT);
pinMode(WaitEye, INPUT);
pinMode(StationEye, INPUT);

maybe change INPUT to INPUT_PULLUP so they are not left floating.

Where do these get changed?

boolean StationOCC = true;
boolean LiftOCC = true;
boolean BlockOCC = true;
boolean WaitOCC = true;

I only see them tested in void loop, but never changed.

Add some Serial.print's to see if the variable are getting set to just before the if (... && ... &&...) statements
May turn that something is not wired to the pin think it is