Howdy, I am having a problem with my stepper motors. When I turn on my power supply and then turn on my computer the motors get power to them. However as the computer boots up the motors loose all power. The only reason I can think this is happening is because I run my driver board power from a usb power (5v) and the usb somehow resets as the computer loads (????). Should I be running the boards 5 volt power from a separate supply?
Look www.usb.org and read the standard.
The power available, may not be as expected, and when expected.
In certain cases laptops, for example may turn off the USB power when a lack complex communications have deemed that the power should be off.
Short of a properly designed interface, power may be unreliable, depending on the computer and BIOS design.
Buy a plugpack and you will never have the problem.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.