On Feb 1, 2008, at 8:12 PM, Jon Elson wrote:
[EMAIL PROTECTED] wrote:
Yep! Wilson machine bought a 50' x 4' CMM at a Boeing auction.
Got it
cheap and spent a million moving it and
getting it set up again. And that was only a few miles.
Holy COW! a 50 FOOT CMM? There must only be 2 or 3 in the
entire US that big. (I can understand why Boeing would need
such a machine.)
50 foot at .0001 / Inch resolution would almost be at the limit
for a 32
bit unsigned integer! I could see some
really strange software bugs begin to show up. (Signed vs unsigned
integers). Would a double precision
float handle that?
That's a good point. I vaguely seem to recall the OLD EMC(1)
overflowed the 32-bit raw encoder count into a double float.
The current version just goes to a 32-bit signed value (unless
this has been changed recently). I was wondering if that would
ever be a problem.
Hmm, calculating it, I get 50 * 12 * 10000 = 6 million, which is
not anywhere near 4 billion, or even +/- 2 billion, which is
what the numerical limits of a 32-bit integer are.
I calculate that 2^31 / ( 10000 * 12) = 17896.xxx FEET, which
sounds like it is a lot less of a problem.
Putting a face on it with a bit of arithmetic always helps.
Dave
Jon
----------------------------------------------------------------------
---
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2008.
http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
-------------------------------------------------------------------------
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2008.
http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
