Question of PID control output

Hi geekers,
I find I set different setpoints ,there are same outputs for example setpoint=200,1000,all the output is 2.75v, and I can’t see anything in the Serial.monitor.

#include<PID_v1.h>
double Setpoint, Input, Output;
PID myPID(&Input,&Output,&Setpoint,2,10,5,DIRECT);
void setup() 
{
  Input= analogRead(A0);
  Setpoint = 2;
  Serial.begin(9600);
  myPID.SetMode(AUTOMATIC);
  myPID.SetSampleTime(100);
  // put your setup code here, to run once:

}

void loop() {
  Input = analogRead(A0);
  Serial.print("Input = ");
  Serial.println(Input);
  myPID.Compute();
  analogWrite(DAC1,Output);
  Serial.print("Output = ");
  Serial.println(Output);
  
  // put your main code here, to run repeatedly:

}

and I can't see anything in the Serial.monitor.

Then FORGET ABOUT PID until you figure out why not. It is absolutely pointless to do something complicated when the simple stuff does not work.

Hi Could you please help me figure out my problem? I am really not good at programming code.

void setup()
{
   Serial.begin(9600); // Start really, really slow
}

void loop()
{
   Serial.print("Can you see this?");
   delay(1000);
}

If you run this, and don't see any output, then adding code will be completely useless.

You mean that my Serial.begin(9600)is too low?

I use your code, I can't see anything. I think it is because of my port is native usb port?

I use your code, I can’t see anything.

Where are you looking?

I think it is because of my port is native usb port?

Why do you think that? Why do you think that that is a problem?