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Author Topic: screw mapping backwards?  (Read 3233 times)

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screw mapping backwards?
« on: May 20, 2009, 08:08:00 AM »
hello everyone,

i've started to map my screws, taking data every 2 inches.

i would move to my target, input the actual position and add the point.

When i turn on screw correction, it actually doubled the error at each point.. for example.

i move to 12" on x.  True position is 12.008.  With screw mapping turned on, i get 12.016 as position when i remap the screw.

anything i did wrong?
Re: screw mapping backwards?
« Reply #1 on: May 20, 2009, 11:26:27 AM »
FYI - It is my understanding that screw mapping works only when running G-code, not when jogging.  Basically, it's not particulalrly useful in its current state....

Per Art:

"Screw mapping only works in Gcode. Since Mach3 is a pulse buffering program, its not possible to map for Jog modes and such, so the mapping was written only for program runs in the interpolator. Its rarley used, and I havent looked at the code for a couple years on it. So much work has been done on the interpreter over the past year or so I cant guarentee that its still functional, but you can only expect a result in Gocde run's. Last I looked it was still working fine."

Ray L.
Ray L.
Re: screw mapping backwards?
« Reply #2 on: May 20, 2009, 11:36:18 AM »
Thanks for your reply - that is interesting info

I would assume that since I was executing my movements in MDI that the mapping was taking effect

as soon as I turned mapping off the error went back to my previous numbers

I'll have to play around some more