17jan2019 got all 3 axis running at 1200mm/min no errors for 4 reps of 3Dchips so far |
I saw the on board DRV8825 pololu drivers getting very hot ( losened the glue on heat sinks!)
So i have a fan on them now.
I also saw that X was cooler than Y&Z by a lot.
But thats due to X being used very little in 3Dchips
So I added G10 L2 P0 X0 Y0 Z10 R45 to the program to load X more
Now with fan all drives run cool to touch
I continue repeats of 3Dchips45deg looking for longevity
NB: the DRV8825 has a current limiting pot that needs setting BEFORE hooking up motors for first time
Hahaha the typical very important thing found too late
This current adjustment makes a BIG difference in running
I may have lost a few lives on these cats by not knowing that earlier
got 3 axis cfg running at 5meters per minute :-) 80mm/sec
dunno how fast my drives and machine can handle but this hdwr stepgen works!
got scope shots at 4800mm/min, 12uS pulses at 10Khz (0.0075mm stepsize) CLEAN!
see gallery at bottom pf page
Milestone! I got the picnc board running with SPI comms!
only a simple test so far
but I was able to command 1000 mm move on X axis at 100 scale
I only got the picnc.axis.0.position-fb to respond ( no real hardware yet)
It was hell getting this far but looks like I can get real motion now
A lot of wiring and programming errors were fixed,
mostly due to 'toodamnsmall-and-imgoingblind-itis'
Next, cleanup code and wiring
Dang these SCLK pulses are in the nanoseconds
no wonder the cables have to be as short as possible )
Afterwards, hookup real motors to see if I get faster speeds and higher resolution
( I can get > 2meters/min at full step (.0075mm each) already just bitbanging gpio pins
but I hope for smaller, smoother stepping )
pcbs for PICnc stepgen all built,
but fear set in and i decided to try out some cheap SPI hdwr before using them.
I built dual MCP23S17 boards on ETT protoboards
and they work sweet using a python lib for SPI comms
now i need to write a C driver for them,
then learn about SPI with Linuxcnc, thats all :-)
27 nov 2018 got pcbs from OSHpark and parts from Singapore
couldnt wait for new soldering station so used tiny cheapo gun
its Hakko but still cheapo
update got new Hakko clone, nice to have temp regulation.
pcb looks ok, ohms out ok so far with all SMT on it
see pix at bottom of page
TODONEXT more sockets then testing of SPI link
|| G540, AC entry || http://wiki.linuxcnc.org/uploads/GeckoRear.png || 48V Kelling|| |
|| G540, AC entry || http://wiki.linuxcnc.org/uploads/GeckoRear.png || 48V Kelling|||
|| PICnc v2.1 top || || ||
|| || || PICnc v2.1 bot ||
|| too dang small! || || too dang small! ||
|| openocdprogrammer || || openocdprogrammer ||
|| dual MCP23S17 || || extra 32 io over SPI ||
|| 12uS step pulses || || 10kHz pulse rate ||