I think, I got it so far. I solved the problem (choosing between GUI and CV-In) on javascript level:
for(i=0;i<8;i++)
{
if(Math.abs(oldKnobVal[i]-adc[i])>0.01)
{
knobVal[i]=Math.trunc(adc[i]*100);
oldKnobVal[i]=adc[i];
sendKnobVal(i);
}
}
// knobVal is the value used for showing the knobs in the gui and also sent to the PD ```
// sketch.js only contains this:
var sel;
var labels=["Speed","Time","HF","Feedback","FX Send","Wet/Dry","6","7"];
function setup() {
cnv=createCanvas(600, 780);
loadImg();
sel = createSelect();
sel.position(10, 10);
sel.changed(mySelectEvent);
sel.selected('guitest');
}
function draw() {
displayPanel();
}
And the empty _main.pd is this: