Re: Absolute vs Incremental 3D programming
- From: Anthony <tonytn36sp@xxxxxxxxxxx>
- Date: Sun, 05 Mar 2006 22:12:21 GMT
"Half-nutz" <3t3d@xxxxxxxxxxxxxx> wrote in news:1141594609.022410.33920
I am in shock... To see Anthony type something that I don't agree with!
Although incremental may accumulate errors, it will be accumulating
in the control, and the backlash of the ball screws, use of scales will
to do with the accumulated error.
So, if the controll wants to go to X2.00500 and the salack in the
puts the table at X2.00603 the control will not use the X2.00603 as the
to calculate the next move. It will use the value of X2.00500 as the
starting point to
calculate the position of the next move, since it "thinks'" that that
is where it is at.
Absolute or incremental, the table can be off by the amount of
backlash, but the
control cannot accumulate it.
That is correct, IF you are going in same-direction moves. Not so in
variable direction moves where you have backlash present.
Say you have 0.1 mm backlash in X and Y.
You program X10 Y0
The slide goes to X9.9 Y0 physical position relative to starting point
Now you program Y1
The slide goes X9.9 Y0.9 physical position relative to starting point
Now you program X-10
The slide goes to X0.2 physical position relative to starting point
Now your slide sits at X0.2 Y0.2 physical position
Remember that in incremental mode, your Zero point becomes the point you
stopped at. It is not referenced to anything other than present
position. It will move what you tell it from where it is at.
Your backlash will become additive every time you change directions.
You can't 'idiot proof' anything....every time you try, they just make
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