# PID Library question

**URL:** <https://community.particle.io/t/pid-library-question/55526>\
**Category:** Firmware\
**Created:** [April 6, 2020, 9:34am UTC](https://community.particle.io/t/pid-library-question/55526 "2020-04-06T09:34:49Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![hydrotruth](https://avatars.discourse-cdn.com/v4/letter/h/d6d6ee/32.png) [@hydrotruth](https://community.particle.io/u/hydrotruth)\
**Post date:** [April 6, 2020, 9:34am UTC](https://community.particle.io/t/pid-library-question/55526/1 "2020-04-06T09:34:50Z")

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Hello to all.

I would like to incorporate the pid library with the Adaptive tunings example on a Photon.  
In particular I need to replace the Output to a servo angle, just a little stumped on how to go about that.

Input will be analogRead and Output should be servo angle.  
If setpoint is analogRead = 2048;  
myServo.write(90); //minimum is 45degrees, maximum is 135degrees

Any assistance would be appreciated.

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<div class="post-metadata">

**Author:** ![ScruffR](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/scruffr/32/6952_2.png) [@ScruffR](https://community.particle.io/u/ScruffR)\
**Post date:** [April 6, 2020, 10:08am UTC](https://community.particle.io/t/pid-library-question/55526/2 "2020-04-06T10:08:48Z")

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Not sure how this pertains to the PID library, but in order to map a reading in the range of 0…4095 to a range of 45…135 you’d just use `angle = map(setpoint, 0, 4095, 45, 135)`.

Or simple algebra would do the trick just the same - after all that’s what `map()` uses internally 😉

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<div class="post-metadata">

**Author:** ![hydrotruth](https://avatars.discourse-cdn.com/v4/letter/h/d6d6ee/32.png) [@hydrotruth](https://community.particle.io/u/hydrotruth)\
**Post date:** [April 6, 2020, 12:45pm UTC](https://community.particle.io/t/pid-library-question/55526/3 "2020-04-06T12:45:10Z")

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Thank you ScruffR.

I have tried to adapt that to the below example.  
Getting a map overload error.

```auto

/ ********************************************************
 * PID Adaptive Tuning Example
 * One of the benefits of the PID library is that you can
 * change the tuning parameters at any time. this can be
 * helpful if we want the controller to be agressive at some
 * times, and conservative at others. in the example below
 * we set the controller to use Conservative Tuning Parameters
 * when we're near setpoint and more agressive Tuning
 * Parameters when we're farther away.
 ******************************************************** /

#include "pid.h"

Servo myServo; 
#define servoPin D1

//Define Variables we'll be connecting to
double Setpoint, Input, Output;

//Define the aggressive and conservative Tuning Parameters
double aggKp=4, aggKi=0.2, aggKd=1;
double consKp=1, consKi=0.05, consKd=0.25;

//Specify the links and initial tuning parameters
PID myPID(&Input, &Output, &Setpoint, consKp, consKi, consKd, PID::DIRECT);

void setup()
{
    
  myServo.attach(servoPin);  
  myServo.write(90);
  
  //initialize the variables we're linked to
  Input = analogRead(0);
  Setpoint = 2048;

  //turn the PID on
  myPID.SetMode(PID::AUTOMATIC);
}

void loop()
{
  Input = analogRead(0);
  Output = map(Setpoint, 0, 4096, 45, 135);

  double gap = abs(Setpoint-Input); //distance away from setpoint
  if(gap<10)
  { //we're close to setpoint, use conservative tuning parameters
    myPID.SetTunings(consKp, consKi, consKd);
  }
  else
  {
     //we're far from setpoint, use aggressive tuning parameters
     myPID.SetTunings(aggKp, aggKi, aggKd);
  }
  
  myPID.Compute();
  myServo.write(Output);
}

```

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<div class="post-metadata">

**Author:** ![ScruffR](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/scruffr/32/6952_2.png) [@ScruffR](https://community.particle.io/u/ScruffR)\
**Post date:** [April 6, 2020, 12:49pm UTC](https://community.particle.io/t/pid-library-question/55526/4 "2020-04-06T12:49:04Z")

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Since you are using a `double` for `Setpoint` your number literals also need to be floating point types otherwise the compiler wouldn’t know whether to make `Setpoint` an `int` or the 4 integers into `double` - hence the ambiguity error.

This will provide the required hint

```cpp
 Output = map(Setpoint, 0.0, 4095.0, 45.0, 135.0);

```

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/particle/original/3X/3/2/3291e3c9351789fe8620ae5bcec8d3fec67ff221.png) [@system](https://community.particle.io/u/system)\
**Post date:** [October 6, 2020, 12:49am UTC](https://community.particle.io/t/pid-library-question/55526/5 "2020-10-06T00:49:11Z")

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