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New Computer, now stepping problem
« on: September 28, 2011, 06:58:35 PM »
Hi

I have been running Mach3 on a K2CNC with stepper motors for a couple of years, no problem. The CNC computer failed so I bought another. Now when I "Go To Zero" which I believe is a full speed move, the motors just sit and squeal. Yet I can reference home and jog OK at lower speeds. With drivertest the old CPU was testing at about a 1800, the new CPU is testing at 3400. Still running 35Khz as I did with the old machine. Configuration was copied over exactly. Parallel port is outputting 5 volts. I also tried a PCI parallel port card and the same thing happens.

If I could I would underclock my CPU but the BIOS only allows overclocking.

Been poking around with some setting with no results. Any pointers?

Thanks

Offline DAlgie

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Re: New Computer, now stepping problem
« Reply #1 on: September 29, 2011, 12:33:34 AM »
If you updated Mach with a newer version when you went to the new computer, this may be your problem. I updated to a new version and then couldn't run the same speeds as before for some reason. I just had to set the max motor speeds lower.
Re: New Computer, now stepping problem
« Reply #2 on: September 29, 2011, 03:59:57 PM »
Well here is the solution. I find it odd...

With the new computer the velocity and acceleration was too fast. It must have been the old computer could never meet those limits because of CPU speed so the machine ran fine. With the new faster computer I had to cut the accel in 1/2 and reduce the velocity from 100 to 75 ipm.

Offline RICH

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Re: New Computer, now stepping problem
« Reply #3 on: September 29, 2011, 05:16:05 PM »
Quote
With drivertest the old CPU was testing at about a 1800, the new CPU is testing at 3400.

Not sure what you are meaning by 1800 or 3400.  You run the drivertest to see if if there are any problems as they relate to the
kernel speed you are setting. No need to use a higher than required kernel speed and it is related to how manny pulses are required
to turn the motors for a desirable velocity and acceleration. Steppers are limited in usable rpm. Computers vary as to the the kernel speed which can be used. As you have found out the user should check the tuning of the motors and not assume past settings will work.

May want to mention what version of Mach you are using.

Glad you got it working, :)
RICH