Feedback gain, % per degree error Feed-forward gain, % per degree
Demanded temperature: Ambient = 20

<![CDATA[function setup(){ t=0; tmax = 200; demand=40; ambient=20; tank=ambient; pipe= Array(100); for(i=0;i<101;i++){pipe[i]=ambient;} tout=ambient; a=0.1; // Time constant about ten seconds b=7; // Will give 70 degrees temperature rise for u=1. dt = .1; fbgain=document.getElementById("fb").value/100; ffgain=document.getElementById("ff").value/100; ScaleWindow(-5,-5,tmax,110); DrawAxes(0,0,tmax,100); Label('Proportional+FeedForward',120,85); Colour("black"); Label('Output temperature',120,80); Colour("blue"); Label('Target temperature',120,75); Colour("red"); Label('Power %',120,70); Colour("black"); t = 0; i=0; MoveTo(t,tank); loop();]]>
<![CDATA[ function loop(){ u=demand*ffgain+(demand-tout)*fbgain; if(u>1){u=1;} if(u<0){u=0;} tank=tank+(a*(ambient-tank)+b*u)*dt; tout=pipe[i]; pipe[i]=tank; i=i+1; if(i>99){i=0;} t = t + dt; Colour("blue"); Spot(t, demand); Colour("red"); Spot(t, u*100); Colour("black"); Spot(t, tout); if (t<tmax){setTimeout('loop()',10);} } ]]>