Hi,
I am working on a project that requires two high speed PID loops for generating PWM waveforms that control current and voltage of downstream equipment. The PWM waveforms are generated via IntervalTimer interrupts and there is no issue there. The duty cycle of the PWM requires a finer control compared to 0-255 default and that is why I am using intervalTimer interrupts
However I am unable to properly use any of the PID libraries I could find online. I was able to get the PID_v2 working as a simple PID controller but am unable to find proper documentation for how to define the output limits and also how to change the gains during normal running of the code as the operator may need to make changes to the gains
The PID_V2 reference page takes me to the github page where there isnt much info on the functions: https://github.com/imax9000/Arduino-PID-Library
There is a link to the old PID function list but if I try using any of the functions they show the following error during compiling eg:
error: 'SetOutputLimits' was not declared in this scope
SetOutputLimits(0, 1000)
^
'SetOutputLimits' was not declared in this scope
If I try using the function as below, nothing happens and the output limit is still the default 0-255
bool SetOutputLimits(0, 1000);
Link to original PID reference page: https://playground.arduino.cc/Code/PIDLibrary/
Please guide me on how to use the PID Library or if there is another library that you use for Teensy with clear documentation it would be a huge help. I have been going crazy searching online and coming up with nothing useful.
Would really appreciate direct references to any code or websites/libraries with working code instead of just someone telling me to google something
The code I was using is just a modified version of the Simple PID example to take a potentiometer input and change the brightness of the onboard LED and basically see the output changing as the pot values are changed manually. This isnt the proper implementation of a PID but its just to simply check that the output limits change with code (does not max out at 255 and maxes out at the value I require, also that gains change with commands from the code and dont stay at what they were initialized at). Again this is not my final code but just a test code to see if the PID library generates any output and if that output can be configured to the limits and changing gains required in my final code.
Test program code:
I am working on a project that requires two high speed PID loops for generating PWM waveforms that control current and voltage of downstream equipment. The PWM waveforms are generated via IntervalTimer interrupts and there is no issue there. The duty cycle of the PWM requires a finer control compared to 0-255 default and that is why I am using intervalTimer interrupts
However I am unable to properly use any of the PID libraries I could find online. I was able to get the PID_v2 working as a simple PID controller but am unable to find proper documentation for how to define the output limits and also how to change the gains during normal running of the code as the operator may need to make changes to the gains
The PID_V2 reference page takes me to the github page where there isnt much info on the functions: https://github.com/imax9000/Arduino-PID-Library
There is a link to the old PID function list but if I try using any of the functions they show the following error during compiling eg:
error: 'SetOutputLimits' was not declared in this scope
SetOutputLimits(0, 1000)
^
'SetOutputLimits' was not declared in this scope
If I try using the function as below, nothing happens and the output limit is still the default 0-255
bool SetOutputLimits(0, 1000);
Link to original PID reference page: https://playground.arduino.cc/Code/PIDLibrary/
Please guide me on how to use the PID Library or if there is another library that you use for Teensy with clear documentation it would be a huge help. I have been going crazy searching online and coming up with nothing useful.
Would really appreciate direct references to any code or websites/libraries with working code instead of just someone telling me to google something
The code I was using is just a modified version of the Simple PID example to take a potentiometer input and change the brightness of the onboard LED and basically see the output changing as the pot values are changed manually. This isnt the proper implementation of a PID but its just to simply check that the output limits change with code (does not max out at 255 and maxes out at the value I require, also that gains change with commands from the code and dont stay at what they were initialized at). Again this is not my final code but just a test code to see if the PID library generates any output and if that output can be configured to the limits and changing gains required in my final code.
Test program code:
Code:
#include <PID_v2.h>
double Kp = 2.1, Ki = 20.5, Kd = 0;
PID_v2 myPID(Kp, Ki, Kd, PID::Direct);
int potPin = 0; //A0
int potValue = 0;
int ledPin = 13;
void setup() {
myPID.Start(analogRead(potPin), // input
0, // current output
100); // setpoint
Serial.begin(9600);
}
void loop() {
const double input = analogRead(potPin);
const double op = myPID.Run(input);
analogWrite(ledPin, op);
Serial.println(op);
}