I don't have a copy of the code handy, but for my table, I modified the thc
component to have two different correction velocities. The slower velocity
is used when the actual voltage is close to the set-point and the faster
velocity is used otherwise. Both velocities and how-close-is-close are set
with hal pins (or parameters).
On Tue, Jan 24, 2017 at 8:44 AM, John Thornton <j...@gnipsel.com> wrote:
> Thanks for that code, I looked at pid.c a few times but > 600 lines of C
> made me dizzy. Let me see what I can do with that.
>
> JT
>
>
> On 1/24/2017 7:29 AM, andy pugh wrote:
> > On 24 January 2017 at 00:06, John Thornton <j...@gnipsel.com> wrote:
> >> if(enable){
> >> float min_velocity = requested_vel
> >> -(requested_vel*(1/velocity_tol));
> >> if(current_vel > 0 && current_vel >= min_velocity){vel_status
> = 1;}
> >> else {vel_status = 0;}
> >>
> >> if(torch_on && arc_ok && vel_status){ // allow correction
> >> //if(volts_requested - volts > volts_limit){
> >> // volts = volts_requested - volts_limit;
> >> //}
> >> //else if(volts_requested + volts > volts_limit){
> >> // volts = volts_requested +volts_limit;
> >> //}
> >> if (abs(volts_requested - volts) > voltage_tol) {
> >> offset += (volts_requested - volts) * p_gain;
> >> }
> >> last_z_in = 0;
> >> }
> >
> > The code for an actual PID is pretty simple.
> >
> > static double olderror, iterm
> > if(torch_on && arc_ok && vel_status){ // allow correction
> > error = (volts_requested - volts)
> > dterm = (error - olderrer) * Dgain
> > olderror = error
> > iterm += error * Igain
> > pterm = error * Pgain
> > if (absf(error) > deadband){
> > offset += pterm + iterm + dterm
> > }
> >
> > Is close. You probably need to initialise olderror intelligently, to
> > avoid a single-cycle crazy value.
> >
>
>
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