I think that instead using Arduino as a PID controller, you could use it only as interface between a PC and the process. In this way, you could program the PID controller in Matlab or Labview.

// global variables double e2, e1, e0, u2, u1, u0; // variables used in PID computation double r; // command double y; // plant output // these parameters should be user-adjustable

double Kp = 10;

// proportional gain double Ki = 1; // integral gain double Kd = 1; // derivative gain N = 20; // filter coefficients Ts = 0.01; // This must match actual sampling time PID // controller is running // -- the following coefficients must be recomputed if // --- any parameter above is changed by user a0 = (1+N*Ts); a1 = -(2 + N*Ts);

a2 = 1; b0 = Kp*(1+N*Ts) + Ki*Ts*(1+N*Ts) + Kd*N; b1 = -(Kp*(2+N*Ts) + Ki*Ts + 2*Kd*N); b2 = Kp + Kd*N; ku1 = a1/a0; ku2 = a2/a0; ke0 = b0/a0; ke1 = b1/a0; ke2 = b2/a0;

// implement this as timer interrupt service routine void pid(void)

{ e2=e1; e1=e0; u2=u1; u1=u0; // update variables y = read(); // read plant output e0 = r – y; // compute new error u0 = -ku1*u1 – ku2*u2 + ke0*e0 + ke1*e1 + ke2*e2; // eq (12) if (u0 > UMAX) u0 = UMAX; // limit to DAC or PWM range if (U0

Mohamed Abdelhady , Thank you so much for your comment! Your formulas are exactly how we are approaching the situation and it is reassuring to see that this is a good approach.