I've configured my A axis as linear by unchecking "A axis is Angular" on the General Config page.  Nevertheless, when I give a code a move in the negative direction, the axis moves in the positive direction as if it were angular.  I have determined that if on the General Config page I uncheck the "Rot 360 Rollover" the axis behaves as I want a linear axis to do. 

Unfortunately, this means that I cannot use the Rollover feature on my B or C rotary axes.  This appears to be a bug in the Mach 3 software.  Does anyone have any comments or suggestions?

By the way, I have also found I can have the axis operate correctly as a linear axis even when the "Rot 360 Rollover" box is checked, but this requires going to Incremental Mode (G91) and out again every time I want to move in the negative direction.

I remember a conversation with Art Fennerty when he said checking "A axis is Angular"  does one thing and one thing only.

That is, it tells Mach3 to NOT scale the A axis DRO when changing from G20 to G21 or vice versa.  Nothing else.

So that would suggest to me you may be stuck with this particular issue.

Thanks for the advice.  Disappointing but at least there is a work-around.  I may see if I can build a "Brain" to do what I want.