I'll put my two cents in here too. First I had to buy a 3A 5V supply because the 2A kept making the lightning bolt show up at the top right corner of the screen. Measured with a 6 digit meter it showed about 4.86V So make sure you have a decent 5V supply. I'd suggest at least 5A and not something cheap. So now the price of the Pi goes up a bit.
I'm using the MESA 7i92H to a PMDX126 BoB. I was using the C11 pin file for that since it matched the step pin2, dir pin3 model better than the PMDX one which had dir pin2 and step pin3. Since then I have modified the C11 VHDL file to shift a few things around, opened up pin 10 to be GPIO for the ESTOP which moves the encoder down 1 pin and now I can try a quadrature encoder on the spindle. Peter Wallace compiled the VHDL file for me and I just installed the .bit file and it works perfectly. I've noticed that occasionally on start-up I get the warning message that the system may not be fast enough. Not sure why. I haven't run the latency test and keyed the results into the HAL or INI file so that may be why. I'm also only running a 1GB Pi4 and I've read somewhere that LinuxCNC on the Pi prefers 3GB so a 4GB Pi4 would be better. Perhaps some sort of paging is going on during start-up that slows things enough to cause the message. A friend has a 4GB Pi4 coming in and he's got the same 7i92 so he might see the problem or he might not. I also don't remember if I had WiFi enabled the last time I tried it and if that's also a reason for the delays. Normally I don't like to have the shop machine the network. As far as a PI4 being fast enough for an encoder one shouldn't care. It's the FPGA on the MESA board that's counting that. Not a parallel port or 3 GPIO pins on the Pi. The Pi4 excels at display handling so I don't think that's a weak spot. The SD card might be. Absolutely fastest possible should be purchased. All these things do start raising the price over a surplus PC. Since the Pi4 has two USB 2.0 and two USB 3.0 there's usually enough for: 1. USB dongle for transferring G-Code 2. Keyboard 3. Mouse 4. Pendant. And now you are out of space. Some of the desktop PCs now come with about 7 USB ports so add the price of a dangling dongle USB hub. Best it be USB 3.0 I think the Pi4 4GB with a MESA Ethernet connection will be ideal and all the stuff including the BoB and power supply will fit into a smaller box than a desktop PC. So if a compact footprint is the goal it's not a bad idea. But be aware you are at the front end of the experience curve here. Most people are still just experimenting with it as a CNC controller. I have no idea how many out there are now in a box, the lid or door closed and just being used to CNC parts without thought that it's a Pi doing the work. For the price of a Pi4 which can be repurposed (I'm using a Pi2 on my Octopi 3D printer) and a decent power supply (never a waste of money) you can play for a while and if you aren't happy put in the big 64 bit PC. My two cents. And in Canada we don't use pennies anymore so for what it's worth. John > -----Original Message----- > From: Leonardo Marsaglia [mailto:ldmarsag...@gmail.com] > Sent: June-12-21 4:25 PM > To: Enhanced Machine Controller (EMC) > Subject: [Emc-users] Question about Raspberry Pi 4 reliability > > Hello guys, > > As some of you know, I'm finishing a CNC router and I'm about to purchase > all the control hardware. I know Gene, John, and several people here are > running LCNC on the PI with success but I would like to know how much of a > pain in the ass is to get it running well with a 7i76E for controlling the > router. > > I'm trying to decide wheter I purchase Rpi 4b or I use a normal PC as I've > been doing with all the other machines. I really like the idea of using > something as portable and small as the Rpi but I don't want to purchase one > just to test right now... I do have a Rpi3 with Octoprint on the ender but > I don't know if that's a good candidate to test LCNC. > > What do you guys think? > > Thanks as always and I hope you're all doing well :) > > _______________________________________________ > 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
