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12-04-2016, 07:49 PM #1
- Join Date
- Jul 2016
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- Pennsylvania, USA
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- 255
Hi
So as I understand the thread over on git hub, when the steps go out past 2 ms, bad things happen in terms of catching the 5 ms wide pulse. The MakerFarm's are 4000 steps per mm on the Z axis. At 500 steps / second that would be 1/8 mm per second or roughly 5 mm / minute. My default Z feed is 2 mm / s so it's in the "ok" region. My data before was a default / 10 so 0.2 mm/s. That seemed to work fine on faults. It was junk on spread and one sigma.
Using the above data, to be out around 0.05 mm at 0.2 mm/s your timing would have to be off by 250 ms. If things are sampled at faster than 2 ms, that's a lot of time.
I kinda doubt my one sigma is from timing issues / the machine running to fast. You could trigger the data with a relay and do better than what I'm seeing.
====edit
If you watch the probe long enough as it cycles, you can catch "late" pickup events. The LED "blinks" slightly as it activates. The interesting point is that they do *not* correlate to min or max reading events. The data is still in there with the rest of it.
Contrary to all prior experience, the problem does *not* go away when DEBUG_ALL is invoked. Crazy stuff . So far, it's really hard to see how this is software related.
Off to butcher some poor helpless Marlin functions ....
==== edit
Put a median filter into the probe routine. Running with a fast probe speed (= default on the Pegasus) it improves things by ... surprise! ... square root of the samples (almost). On M48 P40 V4, the standard deviation goes from about 0.030 to about 0.015. With 5 samples that's almost right. There is something else in there other than just 1/F (flicker) noise.
BobLast edited by uncle_bob; 12-06-2016 at 06:40 AM.
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12-06-2016, 07:07 PM #2
Progress is being made!. Now using 1.10 RC7, pretty much everything is up and running and ready for fine tuning with one exception.
During ABL the head will move into position, servo drops down, probing is done (twice 1 fast 1 slow), head moves to next position BUT it does not raise the Z-Axis. As the servo si still down (as I believe it should be), the probe switch drags across the bed.
I have #define Z_PROBE_TRAVEL_HEIGHT 5 is there anything else that needs setting? I must admit I am going a little cross eyed reading through the config files.
Thanks
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12-06-2016, 07:57 PM #3
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- Jul 2016
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- Pennsylvania, USA
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- 255
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12-07-2016, 08:53 AM #4
Hi Bob,
I switched over to RC-Bugfix and ran into problems compiling. With NO modifications to any of the files it compiles OK, but to get the LCD working I need to un-comment the following in Configuration.h
Line 1101 #define DOGLCD // Full graphics display
I can still compile after this.
Next un-comment
Line 1253 #define REPRAP_DISCOUNT_SMART_CONTROLLER
Now the compile fails with:
In file included from sketch\ultralcd.cpp:56:0:
ultralcd_impl_DOGM.h:183: error: 'DOGLCD_CS' was not declared in this scope
U8GLIB_DOGM128_2X u8g(DOGLCD_CS, DOGLCD_A0); // HW-SPI Com: CS, A0 // 4 stripes
.................................................. ..............^
ultralcd_impl_DOGM.h:183: error: 'DOGLCD_A0' was not declared in this scope
U8GLIB_DOGM128_2X u8g(DOGLCD_CS, DOGLCD_A0); // HW-SPI Com: CS, A0 // 4 stripes
.............................................^
exit status 1
'DOGLCD_CS' was not declared in this scope
Unfortunately beyond my expertise to sort that out.
Barry
Please explain to me how to...
05-17-2024, 12:15 PM in 3D Printer Parts, Filament & Materials