[louieatienza]

I had just recently installed a USB SmoothStepper on my machine, and am having issues. I seem to be able to jog all axes no problem and the movement seems smooth. Movements with two axes also seem well.

The problem is when I go to run a job. It's fine going straight in the x,y, or z direction, but the minute it goes into a curve the steppers lose all smoothness to the point where the whole machine starts to shake. I've fiddled with different settings to no avail. Even toyed with the CV settings with no success.

I did download the latest version of Mach3, and the latest SS plugin. Are there other settings in Mach3 that I might have missed?

[mrgiang99]

1/ Unplug all of nother USB devices

2/ for connecting: use the hight quality USB cable with the Ferite ring filter!

[Lee DeRaud]

When you say "curve", is the gcode actually using a G2/G3 arc or is it some kind of short-segment polyline?
ISTR that there's some sort of look-ahead buffer setting that may be too low...

[mrgiang99]

1/ If you draw is a circle as the left figure, it will run smooth but slowly (follow your speed & acceleration)

2/ If your draw is a polyline as the right figure, it will run as shaking.

[Trotline]

Interesting. I'm debugging my newly-built machine, and I'm getting just such results. I'm using an ethernet smoothstepper, and mostly Cambam, which I believe leans more to the polylines. Anyone know if this issue shows up with the ESS?

Thanks

Luke

[TrickyCNC]

Hi Louie

I think you touched on the problem with your CV settings. I believe that is the 'constant velocity' in Mach3 ? (I'm not a Mach user )

I use LinuxCNC, and get the same effects for segmented curves if I use 'exact path' mode, where basically your path is doing a full accel' and decel' on each segment of the curve, which causes the 'shake'. I tweeked the settings to allow a deviation from the path, which solved the problem.

I have no idea how the smoothe stepper system works , or interprets g-code though , sorry. Maybe it doesn't understand the CV code that mach puts out (if it works that way) ?

In linux, the codes are G61 and G64


Rich

[Grunblau]

I had just recently installed a USB SmoothStepper on my machine, and am having issues. I seem to be able to jog all axes no problem and the movement seems smooth. Movements with two axes also seem well.

The problem is when I go to run a job. It's fine going straight in the x,y, or z direction, but the minute it goes into a curve the steppers lose all smoothness to the point where the whole machine starts to shake. I've fiddled with different settings to no avail. Even toyed with the CV settings with no success.

I did download the latest version of Mach3, and the latest SS plugin. Are there other settings in Mach3 that I might have missed?

I was banging my head against this as well. Not for the smooth-stepper, but in Mach3. I suspect you have a similar issue. My solution was to turn off all of the CV 'options' and this smoothed everything out.

Ger21 suggested the following, although I have yet to run a job with them...

The CV angle should not be effecting ±180° moves.
What I do, is leave my CV angle at 89 or 90 (not sure off hand) and turn off CV distance and CV feedrate. It should run OK then.

[louieatienza]

1/ If you draw is a circle as the left figure, it will run smooth but slowly (follow your speed & acceleration)

2/ If your draw is a polyline as the right figure, it will run as shaking.

When you say "curve", is the gcode actually using a G2/G3 arc or is it some kind of short-segment polyline?
ISTR that there's some sort of look-ahead buffer setting that may be too low...

I had used the same file through the parallel port without problems.

I think you touched on the problem with your CV settings. I believe that is the 'constant velocity' in Mach3 ? (I'm not a Mach user )

I had used the same CV settings I had with the parallel port, also tried shortening and lengthening the CV distance as well as different angles.

I was banging my head against this as well. Not for the smooth-stepper, but in Mach3. I suspect you have a similar issue. My solution was to turn off all of the CV 'options' and this smoothed everything out.

Ger21 suggested the following, although I have yet to run a job with them...


Originally Posted by Ger21
The CV angle should not be effecting ±180° moves.
What I do, is leave my CV angle at 89 or 90 (not sure off hand) and turn off CV distance and CV feedrate. It should run OK then.

I hadn't tried that yet, but will give that a shot.

[BAMCNC.COM]

Does/can Mach interpret Gcode into G2/3 if it sees it as a bunch of g1 moves? I'm just having an issue getting g2/3 out of RhinoCam, not sure where the issue is.

Reading this thread made me think more after you drew that picture. Thanks

[TrickyCNC]

is the smoothstepper . or it's drivers, filtering out / not understanding the CV g-codes somehow ?

[Lee DeRaud]

There is a field on the SS plugin config screen, lower-left, labeled: "Number of data points Mach should pre-calculate". Default is 1023 (which certainly sounds like enough to cover this problem), make sure it didn't get set to some really low value by accident.

[louieatienza]

is the smoothstepper . or it's drivers, filtering out / not understanding the CV g-codes somehow ?

If I am not mistaken, CV is exclusive of gcode, and is just how the controller handles certain moves. May also be called a "look ahead" feature in other controllers, that determine the angle from one move to the next, then decide whether to keep at a constant speed through the move or slow down depending on the angle threshold. So really you can have thousands of segments making up an arc and can still have smooth movement.

There is a field on the SS plugin config screen, lower-left, labeled: "Number of data points Mach should pre-calculate". Default is 1023 (which certainly sounds like enough to cover this problem), make sure it didn't get set to some really low value by accident.

I do have it at the default, but it is one parameter I haven't tinkered with yet.

What totally blows is that the manual (which was last updated in 2008) had not been updated with more in-depth explanation of these settings and how they affect performance. while the item description basically calls it "plug and play."

I have made some progress, and have "smoothed" out the motion somewhat by lowering my accel slightly, raising the controller frequency and lowering hte axes frequencies. Still however I get slow-downs between lines, even on a program where I know for sure uses arcs. I am using a USB2.0 PCI card, but haven't tried connecting to the onboard USB1.0 connector yet.

[louieatienza]

I ran a test, using VCarve Pro and a 10" diameter circle cut to a depth of 1" using two 1/2" passes, making three different programs.

On the first, I used a typical profile toolpath, stepping down .5" at a time, at 600ipm feedrate and 100ipm plunge. This was very smooth, and the actual amount of lines for cutting was about 10. VCarve Pro uses I,J to draw the circle. No problem.

On the second program, I used a spiral (helix) ramping strategy using the same feedrate, but set the plunge to 600ipm as well. This made the machine shake vigorously, as VCarve interpolated all the helical movements as short line segments. I think the machined averaged about 320ipm going down the spiral. At the bottom pass VCarve reverted back to I,J commands and the botom pass was as smooth as the first program. Needless to say this program was very long.

On the third program, I used the first, but modified it so that it would helix down using I,J commands. This again was very silky movement and I easily maintained 600ipm throughout the whole program.

I should note that this problem doesn't seem to rear it's ugly head at more realistic cutting speeds now with my tweaked settings, i.e. 200ipm and below. The problem persists however when I use the FRO to speed up a job; it progressively gets choppier the faster I go.

I will try and create some programs with OneCNC and see how they behave with the Smooth Stepper, though with the toolpath optimizations and precision sweeps of the high speed toolpaths, I suspect movement will be smoother.

I did try to adjust up the look-ahead number for the Smooth Stepper but it didn't help much. To be continued...

[ger21]

It's recommended to not use FRO over 125-150%, as it won't run as smooth as if the feedrate was programmed faster. It's a limitation of Mach3, not sure if the Smoothstepper makes a difference there.

Like the others, I think the CV settings may be the answer. Turn off CV Feedrate and CV Distance and see if it helps.

[louieatienza]

It's recommended to not use FRO over 125-150%, as it won't run as smooth as if the feedrate was programmed faster. It's a limitation of Mach3, not sure if the Smoothstepper makes a difference there.

Like the others, I think the CV settings may be the answer. Turn off CV Feedrate and CV Distance and see if it helps.

Thanks Ger... To be complete, I did try the "helix" test programmed at 300ipm and 150ipm. The 150ipm seemed acceptably smooth though not ideal. I didn't see much of a difference between the programmed 300ipm and 150ipm with the FRO at 200%...

[OCNC]

Louie,

Do you use a breakout board? I have a USB Smoothstepper and I've never had a single problem with it. XP Pro; built in USB port; Mach3 with Gerry's screenset; No Breakout Board. I'll have to check the CV settings tomorrow.

Chris

[louieatienza]

Louie,

Do you use a breakout board? I have a USB Smoothstepper and I've never had a single problem with it. XP Pro; built in USB port; Mach3 with Gerry's screenset; No Breakout Board. I'll have to check the CV settings tomorrow.

Chris

No, just straight through to the G540. If you can post a screenshot of the General Config screen in Mach3 and the settings screen for the SS plugin that would help....

Thanks, Louie

[DonFrambach]

What totally blows is that the manual (which was last updated in 2008) had not been updated with more in-depth explanation of these settings and how they affect performance. while the item description basically calls it "plug and play."

I don't understand why the documentation has not been updated especially with the recent ethernet Smooth Stepper version.

I was quite excited about installing a Smooth Stepper on my machine until I learned that the documentation has not been updated beyond its "preliminary" stage and (with a G540 and Mach 3 things work fine for me.) If you get your Smooth Stepper system to work better than with just a G540 and Mach 3, please post what you did and how it works better. I'm VERY interested and I'm certain others are too.

Thanks.

Don

[Lee DeRaud]

I don't understand why the documentation has not been updated especially with the recent ethernet Smooth Stepper version.

Maybe the Mach3 documentation is their role model...

[louieatienza]

Maybe the Mach3 documentation is their role model...

At least the Mach3 manual is pretty extensive. There is absolutely nothing in the SmoothStepper documentation that lists "why" or "how" settings should be made, ot what should be turned on or off in the Mach3 general config, aside from the great help here in the forum. It seems the SmoothStepper guy expects you to be as smart as him to use his product...

Normally I don't have beef about stuff like this, but I never really read through the pdf file before buying the SS, and if I had (and was brave enough to use a different controller software) I would have made a different purchase for sure. Being I have it (and one reason is I have to update my computer) I'll use it, and maybe the situation will be better with a faster computer, but only time will tell. Though, one reason for HAVING the SS os to relieve the CPU from pulse generating duties... aaaaargh....