Jogs slow in all modes
I am setting up my DeskCnc software for a CNC Plasma table and when I jog in slow,med or fast the motors all move at a snails pace. I am new to this and don't know much about setting up the parameters in DeskCnc. Where should I start?
1) have you determined the spi (steps per inch of servo / stepper revolution) ? What is your encoder count per rev?
2)Open desk CNC with the controller energized.then go to Machine Set up and then to Machine Velocities these are suggested settings to get you going you must do the math for the machine you own.
Machine velocities (sps) Acceleration= 125,000
Accel scale= 10
Start Velocity= 250
Fast Jog = 800.00
click 60-125,000 sps.
click save and close Desk CNC
and go back to machine set up, click Axis Set up
X axis I just put 0.00 for Home and Home offset
then steps per inch= your calculated spi ( E mail me if you have a problem with spi)
Max vel( sps) = 25000 ( or you can try higher..again it depends on the machine, reduction and lead screw) do not exceed 50,000 sps and it should match your max velocity in machine velocities set up. click save and close Desk CNC.
do the same in Y and Z axis if the reduction and lead screw are all the same numbers.
If you are still having problems, E mail me with the encoder count,reduction to the lead screw and the lead count, and hopefully we can send the right set up to you...I will admit the initial Desk CNC set up was very hard for me
( Klutz-Newbie), but after doing it correct, the machines will haul a__
Also, Fred Smith at IM Machining ( firstname.lastname@example.org) has out lined all of the above, and it can be down-loaded at no cost..including a step by step procedure of trouble shooting and supported G codes..If your going to use Desk CNC, you need that info, it is very helpful, especially the G -code syntax
That web site has all the info and down loads to really help you make a successful machine using Desk CNC.
Adobe (old as dirt)
Ok, thanks for your help so far.
I followed your exact intructions except for Steps per Inch (SPI). For this parameter, I put a arbitrary value in. If you can, show me a formula or a way to figure this value out.
My encoder count is 200. The reduction to the rack is as follows:
Motor --- 10----60 ---- 13
I'm using a rack and pinion setup.
The rack has ~7 teeth per inch.
Nevertheless, the jog mode (fast, med, slow) still remains slow. When the value of the jog is changed in the machine setup, it is accepted. Then, on the machine mode screen, I go to the pull-down box and select (fast, med, or slow). On the computer screen, the feedrate value does change to the new value but the machine does not react in the same manner.
But...when I select a incremental movement (i.e. 5., 1.), the machine axes do move a bit faster according to velocity and accel. settings. This option works great but not the jog mode.
I also forgot to mention that I am using Gecko 340s compared to Gecko 320s. I doubt it has anything to do with it but maybe. I think the only difference is the multiplier.
Ok, the 200 count encoder yields 800 steps per servo revolution. If your servo / stepper is capable of 3000 RPM that would =2,400,000 steps per minute, divide by 60 =40,000 steps per second max in G00. Go back and change the Max velocity in machine velocities to 40,000 steps per second.click the "tab" button on your computor and it will high light " start velocity", change that to 400. click save, and close Desk CNC.
Re-open ( I should mention that when doing this you should see " Controller not detected", both when you open Desk CNC and when you hit save, if not turn off the controller and the servos )Desk CNC, go to machine set up and click "axis set up"
Now as I understand your figures above:The motor pully has ten teeth, the reduction pully has 60, so that reduction is 6 to 1.I assume the rack has a 13 to one reduction ?? ? ? Wow, if so 13 to 1 times 6 to 1 is a total reduction of 78 to 1 ! Then the lead is 7 times 78 = 546 revolutions of the servo to advance one inch..? at 3000 rpm (servo), your going less than 3 IPM..So I must not of understood the 13 number above..? or my funny pills got me going.
The max vel (sps) in the "axes set up page " should =40,000 sps. If I correctly understood the 13 is a reduction at the rack of 13 to 1, then at a maxium of 40,000 sps (3000 servo rpm ) it still only caculates to to less than 3 IPM.. software is most likley limited to 50,000 sps (3,000,000 spm),I would doubt that even a max of 50,000 sps, you would move much faster.
Lets resolve what I think is my misunderstanding of the rack reduction, then we can go from there..
Adobe (really old today)
Berk60 and I are working on this project together at work.
The motor pulley has 10 teeth, the reduction gear does have 60 teeth, but that is it. There is no other reduction gear. From the 60 tooth reduction gear, a pinion is connected to drive on the rack. It's a one to one.
Adobe, the reduction would be 6:1 and 1:1 = 6:1. Yea. That other reduction is not right
I think the software limit for sps is 45,000.
Another thing is when we set our parameters. We have not been shutting the machine down to make sure the controller is disconnected. We will try this in the future.
Last edited by vintage; 01-05-2007 at 10:38 PM.
ok cool, uh, what was the 13 in the above ? Anyway there is a 6 to1 ratio, 7 on the lead, that is 42 servo turns / inch..lots better.
set up your axis spi ( in axis set up ) to 33600.000 for some reason you must have the decimal point and the trailing zeros. (or 42 times 800) that should give you the correct steps per inch. You may have to adjust the spi a little bit..If the axis travel is to long ( for a 1.00 jog) reduce the spi..( with your ratio, there should be 33.6 steps per .001, too short, add steps per inch.
This is not a backlash adjustment, only fine tuning the servos and software. At this time do not screw with backlash steps ( just put 100) until everything is running ,and there is some hours of motion on the axis.
Set up max vel (sps) at 40,000. ( you may need to lower that number, will explain below).
Click save ( again you should see the statement "controller not found", which is correct.close Desk CNC,then re-open to the Machine Velocities page in set up.
Fast jog velocity at your reduction : Try fast=1600, medium = 700,
Then check speed range 40-125,000 sps.next look at your accel graph, does it start in the lower left and go to the upper right in a pretty straight line ?
is the time ( under the graph ) over 0.2 seconds.. ? If the servos fault when you go to G00, or when all axis are in G01, drop the Max. Velocity to say 35000..I had to experiment a little, but you have some real good servo amps, so you may be able to run at 40,000 to 45,000 sps with no problem.
There may be one other part of the set up you need to do: Under set up again, the last item is " Modify accel ramp".. You can modify the ramp if necessary..when you open it up you will see how you can reconstruct the accel ramp..takes awhile, but I was able to get it much smoother.When you are finished , tap " Download accel ramp to controller" then "set and save"
The Mill was easy, only took once, but my lathe took three times to get it the way I wanted.
Keep us informed.
Adobe (old as dirt)
There may be one issue here. When you open Desk CNC, you should see the statement " controller not detected", also you should see that statement any time you save the changes. We are only changing the soft ware not the controller..On my machines I have seperate relays for the controller, the servos and the accessories. Your machine may not be that way. Essentially you could make the changes in an other room on you computor, then hook up the computor to the machine and controller..hope that helps !
Adobe (old as dirt)
Thanks for all the good info. I can't wait to try in the A.M. I will let you know how it works.
There are some other things that should be mentioned :
1) make sure your in "inch mode", if your going to use metric, then all of the above must be changed. ( That is in set up, "Desk CNC")That would make a huge differance in velocity settings.You should change "Jog distance" (same page) to 0.001., any larger and you might get suprised when you hit an axis key. I also check " High Light G code, makes it easier to edit.
2) Make sure that "2nd gen" controller is checked ( Machine page ), and on that page check the correct number of axis ( top left). check " Meter in backlash comp" for when you set up your backlash later.
3) "Break arcs into lines", put 0.00001 ( Machine page)
Adobe (old as dirt)
Take a look at the attachments I have sent of the set up screens in deskcnc. I think I must have entered the parameters you gave us wrong or something because the line in the graph isn't at much of an angle.
Also the controller says, Filmware ver. 1.38 on it. Is that a 2nd gen controller?
What do you think?
Sorry, little slow getting back to you. What I did , using your reductions and lead info, was to go to one of my machines using DESK CNC and set up the following for a safe machine. The figures are conservative, but will get you going, then you can add from there untill the servo's fault or the machine says
AXIS PAGE 1ST
One change only..change max sps to 25000 ( note you used 3500, make sure the change is to thousands) on all axis..
MACHINE VELOCITIES PAGE
Acceleration = 125000
Max Velocity= 25000 (to match Axis set up)
Start Velocity= 2500
Jogs = 1000,600,200
I ran my machine for 2 hours plus (not cutting ) had no faults, every thing worked correct..Little slow, but you can start here.
I do not know why your DeskCNC is so old, but my advice is to go to
www.deskcnc.com and hit "contact"..they will drop down an E mail form, just tell them your version and ask if you can download the latest version.
I had a corrupted file in my 2nd DESK CNC, and I downloaded from them (they must be the distributor in the US ) and it was a newer version.The newer versions are faster, go to 50000 sps and have some other nice features.I was not charged for the newer copy. You will have to fill everything in again, but you should be pretty fast by now, right ? Remember it is a hobby, and you are having fun.. right ??
Have you downloaded the info from IM Service yet..That is real valuable, especially the G Code explinations and the troubleshooting manual, both prepared by Fred Smith at IM Serv, and at no cost..
When you get past the set up, you will find that this is a very good program:
With the "look ahead" features, it will slow down before changing directions, avoiding jerks and thumps...which means better control of tolerances..etc.After using a couple of times I'm sure you will enjoy the ease and simplicity of DeskCNC..I did struggle with the set up too..
Hope this helps, and post some pictures of your project, I am sure a lot of people on the fourm would like to see them..Keep us posted.
Adobe (old as dirt)
No feed rate control on lines
Well we have everything working good except there is no feedrate control on G01 line moves , it doesn't matter what we put the feedrate at in G code, it travels at the same rate. We do have feedrate control of circles since we unchecked the box in Machine Config. to Break Arcs into line. You will notice that we only have 2 axis checked for now, we will worry about Z latter. I have attached all our set up sheets for you and a pic of the machine.
What do you think the problem may be?