PID library output is limited only 255

[ahmadazzam2000]

So I want to make a closed loop VSD system with PID, I use the MCP4725 DAC which can output up to 4095 (12bit) as the analog input to the VSD. input here I use "kecepatan" (rpm measurement), Setpoint uses "kecepatanSet" (rpm set, by operator). But if I use the PID library, the output only reaches 255. I want the output to only reach 4095, not just up to 255, I'm a newbie in coding, can anyone help me?

#include <PID_v1.h>
#include <Adafruit_MCP4725.h>

//Define Variables we'll be connecting to
double Setpoint, Input, Output;
double PIDValue;
//Specify the links and initial tuning parameters
double Kp=1.5, Ki=0.3, Kd=0.01;
PID myPID(&Input, &Output, &Setpoint, Kp, Ki, Kd, DIRECT);

void updatePID()
{
  myPID.Compute();
  PIDValue = Output;
  
}

float checkPid(Adafruit_MCP4725& dac, double kecepatanSet, double kecepatan) {
    double errorSekarang = kecepatanSet - kecepatan;
    Input = kecepatan;
    Setpoint = kecepatanSet;
    updatePID();
    dac.setVoltage(PIDValue, false);
    Serial.println(PIDValue);
    return PIDValue;
}

[J-M-L]

the library has defaults between 0 and 255 in the constructor, the decision there was driven to match the typical PWM values of a small arduino

br3ttb/Arduino-PID-Library/blob/9b4ca0e5b6d7bab9c6ac023e249d6af2446d99bb/PID_v1.cpp#L28C23-L28C23

call SetOutputLimits with your own values in setup()

[TomGeorge]

Hi, @ahmadazzam2000
Welcome to the forum.

Is there a reason you want to control your motor with an analog voltage and not PWM?

How big is your motor?
Can we please have a circuit diagram?
An image of a hand drawn schematic will be fine, include ALL power supplies, component names and pin labels.

Thanks.. Tom..

[ahmadazzam2000]

thanks @J-M-L , it works like a charm. I now just have to tune the PID

[ahmadazzam2000]

hello @TomGeorge , greetings from Indonesia

I use analog input because I use a Schneider ATV12 VSD, instead of making a VSD from scratch. it has several drawbacks, such as open loop, cannot know parameters such as voltage, current, motor speed, etc, and cannot be remote or IoT. so I want to design a system that can cover this lacks of vsd.

The system that I made is dependent on VSD, the VSD that I use can only be up to 0.75 kW, so it can only control motors under 0.75 kW.

for my schematic like the picture below, I made this for my course, it's called a creative project, feel free to use it but please don't use it for commercial purposes hehe