On 3/8/24 12:46, Nicklas SB Karlsson wrote:
tor 2024-03-07 klockan 21:26 -0500 skrev gene heskett:
Greetings all;
one of the problems I am having when using a reasonable speed to search
for the edge of a hole is that it does not stop fast enough on first
contact, and leaves the probe touching the side of the hole as it spins
often enough I get a probe tripped on the next move which recenters the
probe so it can find the next side of the hole.
Since the move in all cases is one to open the probe contact, which a
.1mm move will do, is there a way to make it ignore such a false trigger
during the first few milliseconds of the back to center move? Like
disabling the probe input when its not a z move after a g38.2 probe move?
Sometimes have or had a similar problem. Guess a good solution would be a
distance then moving away from work piece.
I have .ngc files to touch off in different directions. Looking into my .ngc
files for this there first are G38.n move
to probe then probe input is turned off before moving back. Thinking about
again this is not a perfect solution, a
better option would be to only turn off temporary until part is cleared with
some margin but until moved back to start
point should not be a problem.
To normally have probe turned on should be a good idea to avoid jogging into
work piece by misstake, consider this a bug
in my .ngc I found then i should write answer for you. Have sometimes seen
probes with broken tip for sale.
My probe is shop made. A piece of 3/4" teflon rod with a 1/4" tapped
hole for a teflon compression nut bore for a 2.5" long piece of stripped
wire from a short piece of #12 romex cable as straight as can be
manually straightened. Maybe run against something gently to straighten
it better so the tip runs pretty true when spinning. Another stranded
wire from the probe input is split in 2 and wrapped around the 12 ga to
connect the probe input from linuuxcnc And in this case a clip lead from
the table to the rail since its all mounted in plastic by a couple of
twin screw vise I printed to supply a ground to the rail. violates the
heck out of the pick any two out of three rule, simple. expendable and
more than accurate enough for the job. And easily repaired in 10 minutes
if I should damage it. It doesn't care if its bent half a mm as long as
it clears the sidewalls of the hole when reasonably well centered so
there is not any contact at the start of a search move. After thinking
it thru, verified by halscope the no error when not searching hal thing
was being tripped by the blender so I took some timing related stuff
back out and slowed the search vel to 10% and it all just works now.
That .hal fix was, snipping here and there from the hal file:
loadrt and2 names=and_vac,and_lube,and_pid_s_en,steeron,steeroff,and-prb
loadrt select8 count=1
addf select8.0 servo-thread # to control probe sensing
addf and-prb servo-thread # fix for broken select8
#********************************************************
# hook up probe signal but disable if motion type not 5 *
#********************************************************
# this disables out5 if not a probeing move
net probe-ctl <= motion.motion-type => select8.0.sel
net probe-sense <= hm2_5i25.0.gpio.030.in_not => and-prb.in0
net probe-hit1 <= select8.0.out5 => and-prb.in1
net probe-hit2 <= and-prb.out => motion.probe-input
Simple effective, possibly broken by default blender? IDK.
Regards Nicklas Karlsson
Take care and stay well, Nicklas
Cheers, Gene Heskett, CET.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
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