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SmoothStepper USB / Re: Help with SmoothStepper configuration

« on: July 31, 2013, 05:56:44 AM »

I had problems with occasional missed steps using the parallel port on a laptop. I decided to try a smooth stepper to see if it would cure this problem. What happened was that after installing the smooth stepper if I used my usb joypad I started to get random continuous jogs in axes that had not been selected or overspeeding of the steppers where the DRO in Mach3 showed the axis moving but the motors were being driven too fast and were locked and growling. Thought about it for a day or two, tried various setting changes and discussed the problems with a workmate. Suddenly had the thought "what is happening to the usb port power". It seems that when the smoothstepper was in use alone there was just about enough power to work the board. When the joypad drew some power as well the demand on the usb power exceded what was available and the drop in voltage that resulted caused the random problems.

I put a powered usb hub between the laptop and the smooth stepper and the joypad and cured the problem. It seems from what I have read in other threads that similar problems are happening with desktop machines as well as laptops. Since the smooth stepper manual has not been updataed since 2008 as far as I can tell it does not surprise me that this fix is not written up. It mentions external power supplies but does not state how important maintaining the voltage to the board is.

Hope this helps others with these random problems.