Hi all. After not using my cnc for a week, today when I’ve tried running it I’m getting very bad stuttering whenever the machine is trying to interpolate cutting circles (apparently). Instead of smooth coordinated movement it’s very jerky, stopping for maybe 1/2 second then rapidly moving for another 1/2 second. At some points the gsender UI seems to be freezing and unfreezing at about the same rate, and sometimes it seems to freeze completely after cancelling a program. I’m literally cutting air so I don’t think this is a mechanical issue. I’ve reverted to a previous backup of gsender settings and firmware settings, tried both 1.5.1 and 1.6.0 edge, and watched the cpu load/thermals via htop and seen nothing concerning. Can anyone provide suggestions please? Thanks!
@zoidfarb I’ve moved your post to the gSender question category.
Are the files that are now showing the problem files that you have successfully run before?
Ope, sorry bout that. Thanks!
Yeah, I ran the files a week ago without this issue, and have tried a couple different programs to rule out something fishy in the gcode.
I’m going to try running the same code off my laptop tomorrow and see if I can narrow the problem down.
Did you install anything or run an update on the RPi? Is anything else running on it? Have you rebooted it?
Also, which model? the 4, 8, or 16GB version? The 8 should work but I could see it possible stuttering if anything is consuming a lot of RAM, and some programs have memory leaks which slowly eat it up.
I don’t believe I updated anything, though oddly 1.6.0 edge started working better for me (i was having a white screen issue when loading .nc files that went away for no apparent reason).
It’s a 16gb pi, nothing else running, i’ve rebooted, plenty of free memory and cpu cores, though if I’m reading it properly there’s a lot of gpu load. I’ve tried turning off the toolpath preview with no noticable change.
Likely due to the coding of gsender as a whole, taking the video ram. I am not currently running a RPi version for my AltMill so cannot speak to any details but when I firs set everything up I did run gSender on a RPi 4, 8GB. Granted it was an older version of gSender but it ran - albeit slow regardless of what I did with graphics settings.
And with all that said, I am using a gControl with 16GB and it runs Vectric VCarve Pro better than it runs gSender. gSender is slow to load, graphic toolpath don’t always match the physical position, and the timer is usually off.
I just don’t really complain much about it so long as my job runs as expected 
Well, I figured it out. Neither gsender or the pi is at fault, it’s actually backlash compensation causing the ‘stutter’. What’s really happening is the machine is pausing momentarily each time a lead screw is reversed, which happens to be at the 12, 3, 6, and 9 o’clock positions when cutting a circle. When I first noticed the problem I was boring a small hole, so it looked more like a random stutter, but later in the same program an adaptive clearance was having the same problem and I realized that it wasn’t just a random noise issue. I’ll have to look into what’s going on with grblhal and my controller, I suspect I might need to enable Jerk movement or tweak something else.