Wrapping advanced PID library *variable &address problem

[apzeltukas]

Hello, beginner PID does not meet the needs for my project (no limits, hardly suitable for integrating processes etc.)
I want to wrap Arduino PID library into XOD,
https://playground.arduino.cc/Code/PIDLibrary/
https://github.com/br3ttb/Arduino-PID-Library/
but I keep having errors I think originating from the way it requires linking addresses instead of normal values
Library says:
PID(double*, double*, double*,double, double, double, int, int);
Arduino example:
PID myPID(&Input, &Output, &Setpoint,2,5,1,P_ON_M, DIRECT);
one of many my unsuccessful attempts to wrap it up:

// Tell XOD where it could download the library and its dependencies:
#pragma XOD require "https://github.com/br3ttb/Arduino-PID-Library"

// Include C++ library:
#include <PID_v1.h>


node {
    meta {
        // Define our custom type as a pointer on the class instance.
        using Type = PID*;
    }

    //example
    //PID myPID(&Input, &Output, &Setpoint,2,5,1,P_ON_M, DIRECT);
    PID aPID = PID(input_PV,output_OUT,input_SP,input_Kp,input_Ki,input_Kd,input_POM,input_DIR);

    void evaluate(Context ctx) {


        emitValue<output_OUT>(ctx, &aPID);
    }
}

Also tried &input_PV and *input_PV but since I’m basically guessing no wonder it does not work.
Tried learning more, but could not find neither in depth explanations nor similar examples.
can you suggest a solution or an example?

[gweimer]

A big part of your problem is that input_PV, output_OUT, etc. are not just “automagically” variables…you have to create them. I assume you are trying to get these values from pins on your node, so you would need to use getValue. Possible example (assuming input pins Input, Output, SP, parity, etc.):

    auto input = getValue<input_Input>(ctx);
    auto output = getValue<input_output>(ctx);
    auto SP = getValue<input_SP>(ctx);
    auto parity = getValue<input_parity>(ctx);
    [additional code here]
    PID aPID = PID(&input, &output, &SP, parity, [additional params]);

You might have to explicitly define variable types instead of using auto; especially since you are passing pointer to them to existing code expecting specific types.

[xodballxod]

I’ve adapted the XOD PID node to clip and control the ID part sensibly. It appears to be giving the expected result.

pid-control-clip.xodball (26.8 KB)

It applies a defer inside the node, and checks if in-bounds… Then passes the UPD through a GATE on the Integration; allowing Derivative update gives better response. The output is then clipped.

The XODBALL file compares the two PID methods

And works as expected when the value changes

Cheers!
XBX

[xodballxod]

Interesting, the defer has to be where it is… if you try to move it after the CLIP, then it does not work.