Part1     I am new to mach3.  I have a cnc slant bed lathe i am retrofitting to polish  auto wheels.  According to  to my  cad program  the  x axis turns positive  on the way up and negative  on the way down.  Is this correct?.

Part 2    A buffing head  is attached to my toolpost.   I have a logitrol cnc system.  I am  currently manually  polishing wheels by jogging the pendant.   With the pendant  in hand  if i toggle the joy stick up (the polishing head goes" up" as it should , Down as it should) However the dro  indicate   that as i move it" up" past zero   i am going (-)  negative  .  How do i fix this

Yes. zero is on the centre line and all moves from there are positive as you move away, only time you should really be in a negative value on X is when you have moved past centre.

Possibly you need to reverse the X axis and then at the same time reverse the joystick(if thats possible as I have never had one). To see if this is the case move your X via the MDI line. For example if you are at X2 in the DRO do a MDI of G0X3 , it should move up the way, if it moves down then you need to reverse as above.
Hood

Thank  you    Hood.  You hit the nail on the head