For those on this LCNC list who have not seen Klipper, Klipper’s architecture is very much like Linux CNC’s. Like LCNC, the g-code interpreter, kinematics, and motion planning live in a “real computer” like a Raspberry Pi. Or I was running it on a virtual machine running Linux on my Mac mini, Any Linux computer or virtual computer will do. There is no need for a real-time kernel. Klipper is written in Python and is pretty easy to extend with “plug-ins”. All the real-time critical timing is done on a microcontroller. The micro can be even an 8-bit Arduino, but more likely it is an STM32, or RP2040. The micro(s) connect to the Pi with a serial interface, typically USB. Lantancy in the interface is unimportant.
The trick is that the Linux PC sends commands to the microcontroller and each command is time-tagged with the time it should be executed. the microcontroller maintains a queue and does the command at the right time. The Linux PC and the controllers also use a protocol to synchronize their clocks. The time sync works. well enough that you could in theory put each axis on a different microcontroller. The Pi only needs to be fast enough and “real-time enough” to keep the queues full. LCNC really should be doing this. If the Measa cards would maintain a queue and a synchronized clock we would not care at all about latency. Klipper proves the idea works. > On Apr 16, 2024, at 8:46 PM, gene heskett <ghesk...@shentel.net> wrote: > > On 4/16/24 20:46, Chris Albertson wrote: >>> On Apr 15, 2024, at 7:20 PM, gene heskett <ghesk...@shentel.net> wrote: >>> >>> On 4/15/24 21:16, Gregg Eshelman via Emc-users wrote: >>>> I have a Hictop printer with some issues so I'm gathering parts to update >>>> it. Among them is a Big Tree Tech SKR 1.4 board (not the Turbo, which is >>>> identical except runs the CPU 10Mhz faster). >>> >> I assume you would be running Kiper on it. If so, then what isn’t it >> compatible it? It rebuillding a printer and you get to choose a display, >> then by all means use an HDMI touch screen. You can get them for $60 now. >> But any SPI or USB screen should also work. Mostly the screen attaches to >> the Pi. >> BTW, the BTT Raspbery Pi3 clone’s price just “fell throught rhe floor”. >> They are now under $10 in Aliexpress. This means you have to to buy two of >> them to qualify for free shipping. (iIt is kind of a no-brainers to buy one >> %7 Pi3 and pay $$6shipping or to buy two for $7 each and get free shipping.) >> The BTT Pi3 clone runs Klipper on my printer at about 7% CPU load and 35% >> RAM usage. Spending even $35 for a Pi4 is not going to make the printer >> run faster but it would be fun to see the load go from 7% to 4%. The BTT >> clone has a 12 to 24 volt power inpuit using screw terminals, but the word >> is “no higher than 12 volts if you want the Pi to live a long life.” >> I have a BTT Pi3 clone and SKR combo powering my Voron V0.2 “printer for >> ants” and I’m making very nice prints in ABS at up to 340 mm/second. At >> 260c nozzel and 105C bed. The combo is not powerfull enough to drive my 80 >> LED neopixel strip with crazy animations (80 RGBW LEDs updated at 24 frames >> per second) while printing. I have to tame it down while printing. That >> is the only limitation I’ve found with the SKR. But do you really need a >> moving rainbow on the printer while printing? I turned on the effect after >> the print finished to show it is done. > The advantage of fluidd/moonraker/klipper is that all data is presented on a > web page driven by ngnix, I can run the printer, controlling any detail, from > any machine on my home net. I have no idea what the load on the bananapi-m5 > is but its plenty fast enough for at least 10x an Ender5+'s original speed of > around 30mm/sec. I expect my speed limit will be the hot end, its a trinity > labs with a 50 watt cylindrical heater and one piece nozzle/heat break. > >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users > > 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 > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
