Can not read serial!

Hello,

I am trying to make room temp controller with arduino uno and nextion 3.5 display.
Right now i have 4 sensors and 1 relay attached to the board(in the end there should be 5 sensors 4 relays).
My problem is that nextion is showing me the value of sensors but arduino does not read the SET or DIF value if there is multiple sensors (the room SET and DIF turns relay on or off). If there are only one sensor then it reads and works exactly like it should but with 4 sensors it would not.
Maybe somebody can help me. THANKS
Sorry my Inglish

String readString;
int R1S = 200;
int R1D = 20;
int R2S = 200;
int R2D = 20;
int R3S = 200;
int R3D = 20;
int R4S = 200;
int R5D = 20;
String v;
int RelayPin = 5;

void setup() {
Serial.begin(9600);
pinMode(RelayPin, OUTPUT);
}
void loop() {
 int Sensor1_Val = analogRead(A0);
 float voltage = Sensor1_Val * (5.0 / 1023.0);
 float temp = voltage * 93;

 int Sensor1_Val1 = analogRead(A1);
 float voltage1 = Sensor1_Val1 * (5.0 / 1023.0);
 float temp1 = voltage1 * 93;

 int Sensor1_Val2 = analogRead(A2);
 float voltage2 = Sensor1_Val2 * (5.0 / 1023.0);
 float temp2 = voltage2 * 93;

 int Sensor1_Val3 = analogRead(A3);
 float voltage3 = Sensor1_Val3 * (5.0 / 1023.0);
 float temp3 = voltage3 * 93;
 
 if(Serial.available()>0){     
   char c = Serial.read();    
        if(c == '#'){
              v = readString.substring(0);
              if(v=="R1SP"){
                      R1S+=1;      
                           }
              if(v=="R1SM"){
                      R1S-=1;      
                           }
              if(v=="R1DP"){
                      R1D+=1;      
                           }
              if(v=="R1DM"){
                      R1D-=1;      
                           }
            readString="";
                     }
                 else{     
                      readString += c; 
                     } 
              
             
                         }   
             Serial.println();
             Serial.write(0xff);
             Serial.write(0xff);
             Serial.write(0xff);
             Serial.print("page2.x0.val=" + String(temp,0));
             Serial.write(0xff);
             Serial.write(0xff);
             Serial.write(0xff);

              Serial.write(0xff);
             Serial.write(0xff);
             Serial.write(0xff);
               Serial.print("page3.x0.val=" + String(temp1,0));
             Serial.write(0xff);
             Serial.write(0xff);
             Serial.write(0xff);

              Serial.write(0xff);
             Serial.write(0xff);
             Serial.write(0xff);
               Serial.print("page4.x0.val=" + String(temp2,0));
             Serial.write(0xff);
             Serial.write(0xff);
             Serial.write(0xff);

              Serial.write(0xff);
             Serial.write(0xff);
             Serial.write(0xff);
               Serial.print("page5.x0.val=" + String(temp3,0));
             Serial.write(0xff);
             Serial.write(0xff);
             Serial.write(0xff);
             
 
        if((R1S+1) + R1D<temp){        
           set_relay_On();
     Serial.print("page2.x0.pco=1500");
     

   }
   if((R1S-1) + R1D>temp){
     set_relay_Off();
     Serial.print("page2.x0.pco=36496");
     Serial.write(0xff);
     Serial.write(0xff);
     Serial.write(0xff);   
      
   }
}
void set_relay_On(){
 digitalWrite(RelayPin, LOW);
 }
 void set_relay_Off(){
 digitalWrite(RelayPin, HIGH);
 }

N_idis.ino (3.04 KB)

To make it easy for people to help you please modify your post and use the code button </>
codeButton.png

so your code 
looks like this

and is easy to copy to a text editor. See How to use the Forum

Your code is too long for me to study quickly without copying to my text editor.

Also please display your image(s) in your post so we can see it(them) without downloading it(them). See this Simple Image Posting Guide

Have a look at the examples in Serial Input Basics - simple reliable non-blocking ways to receive data.

...R

is there anyone who can help me?

For testing purposes, in your code when you read an analog input, print out the values to the serial monitor that are generated. This may help determine if those functions are working as expected.