Need help with stepper settings

ok so I am building a plasma and have my base machine now set up, I have the mesa 7i96 with thcad 10, for drivers I have leadshine dm556t. I purchased a z axis already complete with floating head and breakaway. Im running the latest master of linux cnc 2.9 on Debian stretch After much tweaking and searching for settings online I was able to finally get some motion but there seems to be major issues. The y axis moves fine when jogging (now that I found how to reverse one of the motors) but the x an z have some problems. when I try to jog either axis the steppers are extremely jumpy, loud and keep moving back and forth different directions. for example I can hit jog left on the x once and it moved left then the next time I press it may move right same with Z. I feel like the problem is in my settings, the Y was acting similarly until I changed the settings under stepper info from all settings at 2500 to all settings at 10000. I really have no clue what I am doing with regards to the settings.

so what I am really asking is what on earth should I set everything to. I currently am going to run direct drive until I can devise a good gear reduction, the gears are 20 pitch 20 degree angle 15 tooth 3/4" pitch diameter running directly on 20 pitch 20 degree angle gear rack. I have no idea what numbers to use for this in the configurator, I also have no idea what kind of micro stepping I should use to strike a decent balance.

as for the stepper settings I have no idea either. the steppers themselves are 4.2 a 425 oz 1.8* step angle run by individual dm556t drivers.

thank you for any help it is much appreciated I need this machine up and running asap i'm just not well versed in all the computer and electronics details.

Aaron3309 wrote: ok so I am building a plasma and have my base machine now set up, I have the mesa 7i96 with thcad 10, for drivers I have leadshine dm556t. I purchased a z axis already complete with floating head and breakaway. Im running the latest master of linux cnc 2.9 on Debian stretch After much tweaking and searching for settings online I was able to finally get some motion but there seems to be major issues. The y axis moves fine when jogging (now that I found how to reverse one of the motors) but the x an z have some problems. when I try to jog either axis the steppers are extremely jumpy, loud and keep moving back and forth different directions. for example I can hit jog left on the x once and it moved left then the next time I press it may move right same with Z. I feel like the problem is in my settings, the Y was acting similarly until I changed the settings under stepper info from all settings at 2500 to all settings at 10000. I really have no clue what I am doing with regards to the settings.

so what I am really asking is what on earth should I set everything to. I currently am going to run direct drive until I can devise a good gear reduction, the gears are 20 pitch 20 degree angle 15 tooth 3/4" pitch diameter running directly on 20 pitch 20 degree angle gear rack. I have no idea what numbers to use for this in the configurator, I also have no idea what kind of micro stepping I should use to strike a decent balance.

as for the stepper settings I have no idea either. the steppers themselves are 4.2 a 425 oz 1.8* step angle run by individual dm556t drivers.

thank you for any help it is much appreciated I need this machine up and running asap i'm just not well versed in all the computer and electronics details.

Can you post the HAL and INI files. Also you need to home the machine before you can jog correctly. Do you have home switches

Can you post the config file of what you tried?

I will post the files as soon as I get home, I do not have the home switches Hooke up yet however I manually clicked the home button which allows me to start to jog. I am certain I have pretty much every number wrong is there base line settings I could use to get a better start? I think I need to just start a new configuration.

You don't need to home to job, unless you specifically told linuxcnc that and if you did it would try to job at all.

Jumpy steppers could be wired wrong or step gen timing number set too tight.
I mean it could be alot of things but those are common.
Thats why when you post your configs we can see whats what.

Chris

You don't need to home to job, unless you specifically told linuxcnc that and if you did it would try to job at all.

Chris. With 2 joints on one axis say X if you try to jog I believe it will only jog the one joint and so will make a mess.

I believe there is away round that by changing from one mode to another ie world mode. But not sure.

Aaron, thanks for reporting in. I don't think you should rebuild your config until you let the guys have a look at your config. There are some timing settings for the steppers in the ini file that may need revising. From this point we'll probably be asking you to edit the files directly in a text editor. I prefer geany which you can install by typing sudo apt-get install geany.

I'm sorry, I'm not up with imperial gears but linuxcnc needs to know how many step pulses per inch of travel. Someone else will know the formula.
So start by calculating the distance travelled per revolution . From what you've said that will be 15 teeth. (measure it along your rack if need be) So multiply that distance by 200 x microsteps, then the scaling is that number divided by inches of travel per rev.

As far as microstepping goes, start with at least 10 x but becasue you have direct drive, this needs to be as high as possible (which changes your pules per inch)

rodw wrote: I'm sorry, I'm not up with imperial gears but linuxcnc needs to know how many step pulses per inch of travel. Someone else will know the formula.

For metric gears the PCD = teeth x module
So, a 20-tooth 2mod gear will have a PCD of 40mm. So it will roll 40 x pi mm down the rack for each revolution.

For Imperial gears the equation is reversed (it's just like TPI and mm pitch...)

PCD = teeth / DP.
So, a 20-tooth 10 DP gear will have a PCD of 2 inches and will roll 2 x pi inches for each revolution.

i have attached my hal and ini files, thank you all for the help it is very much appreciated. this is my first attempt at anything like this and i am in over my head to say the least.

My first guess would be that you have the acceleration too high (~1/3G)

Your acceleration of 136 IPS/S and maximum velocity of 1.66 IPS
means only 0.0123 seconds to full speed. This is likely to stall your step motors

A good starting point for acceleration is about 10X the maximum velocity