M code to "unwind" 4th axis

[mmurray70]

Hi Tom,

I need to make an M code to "unwind" my 4th axis. Im running a 4 axis surface here today and ending up at like 80,000 degrees when its done. Need something to take current A machine position, divide it by 360 degrees and reset position at closest multiple of turns to zero. Same as this:

Im really busy with work at the moment and a little out of practice with c programming, wondering if you might be able to help me with this. Should be fairly simple.Thanks.

Mark

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[machinehop5]

G28A0 maybe

[TomKerekes]

Hi Mark,

See the Modulo360.c example:

If your system has encoders the encoder would need to be adjusted also:

#include "KMotionDef.h"

#define CNTS_PER_DEG 1000.0
#define AXISA 4

double modf(double, double *);    // returns integer part with more than 32-bit precision

double floor(double x)            // truncate down toward -infinity
{
    double y;
    return (modf(x, &y) < 0 ? y - 1 : y);
}

main()
{
    double dest = chan[AXISA].Dest;
    double cnts = CNTS_PER_DEG * 360.0;
    double delta = (floor(dest / cnts)) * cnts;
    WaitNextTimeSlice();        // Avoid interrupts
    DisableAxis(AXISA);
    chan[AXISA].Position -= delta;
    EnableAxisDest(AXISA, dest - delta);
}

[mmurray70]

Awesome, that looks easy enough. Ill give it a try on the next 4th axis job. Thanks again.