Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Bill_O on January 20, 2011, 11:10:44 AM

Title: jerking
Post by: Bill_O on January 20, 2011, 11:10:44 AM

I have a machine that is jerking at move speeds

900 in/min x and y axis
2000 steps/in
kernel speed 65000
step pulse and direction pulse both set at 3
using tempest

It acts like the computer is not keeping up but I need help figuring it out.

Bill

Title: Re: jerking
Post by: poppabear on January 20, 2011, 12:04:12 PM

Hey Bill long time.........

    If you using steppers, they loose power at thier higher RPMs, so mabey they are not large enough for your gantrys wieght at the higer rpms...

check you pulses on an O-Scope at the higher rates, see if you getting a consitant full 5 volts, if you see some fades here and there, that might be the voltage falling below what your drive needs to see, and it misses the pulse.

lastly, it could also be your computer might not be able to keep up, at the higher rates of pulse, it may make a DMA access that puts a "Hickup" at your higher rate.
check your hard drives and see if they are making DMA access or some other program(s) are.

scott

Title: Re: jerking
Post by: Bill_O on January 20, 2011, 12:09:00 PM

Scott,
how do i check for the dma access?
Bill

Title: Re: jerking
Post by: poppabear on January 20, 2011, 12:19:22 PM

Hey Bill,

    it might be easier if you give me a call on my CELL phone.........  (you got my card).
I am in Seattle, WA at my hotel and I have to fly out in about 2 hours.....

scott

Title: Re: jerking
Post by: Bill_O on January 24, 2011, 04:09:02 PM

Scott,

Of course I can not find your card. Please call me if you still have my number when you get the chance.

Bill