Need Help!- Improve/Troubleshoot Parallel Port

[blue_steel]

Hi,

Right now I'm controlling my LJ-II/III steppers directly from my parallel port and a L297/8 driver. I can feel the motors knock or Jerk even though they may not miss any steps.

However when I replace the parallel port input with a 555 timer the motor runs very smooth and I can get much higher RPMs.

I'm using a Windows 98 PC and EZCNC software.

So I'm wondering what I can do to improve the parallel port signal.

Any suggestions appreciated.

Thanks

[Dorsal]

If you download Mach3 from http://www.machsupport.com/ there is a file in the root directory called drivertest.exe that will test the signal qality from your parallel port and give you a graphic of any signal interruptions coming from it. It won't solve anything, but it will give you a solid idea of the problem.
There are also files called SpecialDriver.bat and OriginalDriver.bat to swap in/out some other drivers for your parallel port. I think all three need the Mach3.sys file to run, but can't swear to that.
There may be other sources for these testing files but I haven't looked.

I ran this test on my Dell LatitudeD800 laptop and the results were terrible! Since most printers and such are run from USB ports nowadays, the computer manufacturers are limiting the signal quality and functionality of parallel ports on their computers and yours may have this problem. Dell is the ONLY laptop manufacturer that still has a parallel port on their machines.
I'm on the waiting list to get a SmoothStepper which will run the parallel port card from a USB port (better inherent signal). There are cheap parallel port emulator cards on eBay, but I think it would take a good $100 card to produce an actual parallel port, and for $60 more I can get a real SmoothStepper and be done with the problem. ymmv

You can read here: http://www.phlatforum.com/viewtopic.php?f=14&p=68#p68 to see my post with screenshots of my test results.

[blue_steel]

Thanks Dorsal,

I haven't tried those programs yet since I switched to CNCPro (DOS-based) and it seemed to fix my problem for the time being. My motors now run smooth.

It appears my PC is just a little to old and slow to run a windows program.