M593 Dynamic Acceleration Adjustment no effect

dc42

@alexlin said in M593 Dynamic Acceleration Adjustment no effect:

What do you mean (and why) not use such a low jerk on curves? Do you mean G2/G3 movements? Do slicers generate them?

I don't mean G2/G3 moves, I mean sequences of short straight segments that approximate a curve. If the XY jerk is set too low then the printer will slow down at the junctions between segments.

I will look at adjusting the DAA algorithm to work even when the acceleration limits are low.

AlexLin

@dc42 Thanks , reading your responses in the pressure advance thread explained this

Wyvern

Very cool stuff, I gave this a shot last night and after 2 attempts it killed all the ghosts, along with pressure advance (direct feed) I finally have a perfect single perimeter cube.

My question is so long as I don't set my Acc/jerk too low or too high, the dynamic Acc should stay about the same if I adjust them?

dc42

@wyvern said in M593 Dynamic Acceleration Adjustment no effect:

My question is so long as I don't set my Acc/jerk too low or too high, the dynamic Acc should stay about the same if I adjust them?

I haven't done extensive testing of the effect of changing acceleration and jerk, but this is what I expect:

If you set the acceleration too low in M201 then at higher print speeds, the required acceleration computed by DAA will be above the M201 limit, so DAA won't be applied. The maximum print speed for DAA to be applied at a right angle corner will be about:

V = a/f + j

where a is the acceleration, f is the frequency you are cancelling, and j is the jerk expressed in mm/sec (so 1/60 of the value in M566).

Increasing jerk will reduce the effectiveness of DAA, because it changes the overall acceleration profile from the constant acceleration assumed by the DAA algorithm.

Patrick K

So I am having issues making M593 effective. No matter what F I use, I don't see anything changing.
I bumbed up my vel, my acc and lowered jerk.

From --> to
Vel = 45 to120
acc = 500 to 2000
jerk = 900 to 300

from there my result got instand better even without appling M593. So my ghosting is defenatly depending of frequency. I calculated M593 and depending on my acc (even used 8000 on acc) i got results from M593 F64 till F154.
I ran test where I changed F every mm from 30 to 180. Nothing changed. I did a lot of testing, runing different acc to jerk to frequence matrixes. NOTHING

I figured something only very late and I will have to do some test, but I guess I realized what my issue is.
I am using a high pressure advance value of 1.2. Which gives me charming results.
Therefore I also raised my jerk on E to compensate my high S1.2. So I went from 250 up to 500.

but that seems to little. I think the PA is reducing the Jerk of E so much, that it will influent my motion totally and even impact M593.

My last result I did I ran different setups in changing my motion parameters. After running Vel 120 and acc from 2000-3000 I decided only on the last mm on top to turn of PA and see, no ghosting. not a little. Of course crapy edges but no ghosting.

So I tried with higher jerk for E in PA = 1000. that got me close to the edge of my extruder unit not tu junk or eat the filamet.

So I wonder if there is a way, for me using PA and DAA. righ now I can't see it and I think that might be the issue why most user won't see an effect on DAA. At least with bowden setups as I have.

I assume, to calculattion of the motion profile to avoid certain frequency, is using the jerk and acc values set for x and y. But the actual movement is dictated by the Extruder depending in the PA setting.
Only my assumption.

And just for real lovers, I am running an Omerod2 modified to a monster. (Duet2Wifi and latest firmware to this date)

dc42

@patrick-k said in M593 Dynamic Acceleration Adjustment no effect:

I calculated M593 and depending on my acc (even used 8000 on acc) i got results from M593 F64 till F154.

Ringing frequency does not depend on acceleration. Ringing pitch does depend on the speed at which you print the perimeter (frequency = speed/pitch). At low accelerations, the pitch of ringing will be compressed close to the corners because the head isn't up to speed yet, so ignore the pitch in that area.

Dav

Hi
I calculate my hz but where I've to put the m593 command inside the conf.g?

bot

@Dav You can do that. But, for testing, you can just send it via the web interface so you can enable it only when you want to test it.

Dav

@bot how?

bot

@Dav

So you can put it at the end of your config file:

[...]
M593 F60.1

Or just use the web interface or Panel Due console.

Where it says "Send code..." in the web interface, type M593 F(Your value here) and press enter.