On Sat, May 29, 2010 at 05:44:24PM -0400, Ed Nisley wrote:
> In Axis 2.4.0, is it true that the tool table can have only
> 48-ish entries?
I thought it was 56ish, but yes it's something like that.
> The problem is that Eagle's part libraries have a
> bewildering variety of hole diameters, which means you can't
> tell which drills you need for any given board, even rounded
> off to the nearest 0.001 inch.
Jeff and I solved this problem with some postprocessing: we have a
table that lists what drills we actually have, and the range of
requested hole sizes that we want to drill with it.
> Unfortunately, Axis seems to truncate the tool table to
> about 48 entries. I'd expected that to not be a problem,
> because the doc gives this example:
>
> T99999 P99999 D23.75000 Z-0.3000000 ;You have a
> big tool changer
Well this is a little deceptive/confusing. The basic problem is that
EMC sometimes sends the whole tool table over NML and it expects it to
fit in a fixed size NML buffer. This is generally OK for a machine
even with a fairly big carousel tool changer. We have increased the
buffer size a few times now. Since in 2.4 we now have tool offsets
for all nine axes, each entry is bigger.
As you know there are two specifiers for each tool, the T (tool)
number and P (pocket) number. On a machine that swaps the spindle
tool with a carousel tool ("random" toolchanger) this distinction is
important because EMC rewrites the pocket numbers to keep track of
where the tools are. T can be any number. P must be a pocket number
that makes sense for the machine. P0 is the spindle. P1-P16 (for
example) are the carousel pockets.
On a toolchanger that does not do this ("nonrandom"), including a
manual toolchanger, P is ignored (but read, preserved and rewritten)
by EMC, so you can use P for any bookkeeping number you want. P1xxx
might be the tools piled on the dining room table, for instance. T
can be any number, like above. When EMC reads the tool table, it
makes up pockets as it goes, sequentially, starting at 1. As a user
you will never see this, but as you found out, no matter what your T
and P numbers are, you can only have so many entries.
> Is there a user-level way to increase the maximum number of
> entries in the tool table?
No, you need to set a constant and recompile. Then you have to fix
your nml file to make the tool status buffer big enough.
> In practice, I use only a few drill sizes, because as far as
> I'm concerned 0.023 and 0.024 drills are identical. But the
> script doesn't know which drills I favor, so it lists
> everything it needs. I could stuff those sizes in the tool
> table, but a limit of 50 entries is perilously close to how
> many different drill sizes I actually use: I want to avoid
> having a separate tool table for each job!
Maybe doubling yours would keep you happy for a while. I am not sure
what all would be involved in removing these limitations, and I don't
know of anyone working on it currently. It would be nice if the
tool table could be arbitrarily large.
Meanwhile, I wonder if we could just enlarge it by a factor of 10 or
100 and forget about it for a while. I don't know the problems with
this - maybe someone else will comment.
Chris
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