[Brandon_L]

To add some background to what the above posters said, it sounds like you used two different motor set output VIs for the same motor. The code resulted in one being supplied with a 0 value, and the other with a 1 or 0.6. This will cause it to rapidly stop and start (in a matter of milliseconds) giving it the "sputtering" effect you described.

When controlling a motor, its always best to have a single "Motor Set Output" VI per motor, and manipulating the number being input into the VI through code such as Ether provided. If you stick to this simple rule of thumb of only one VI per motor, you'll never have two values "fighting" each other and giving this effect.

You can use the "Highlight Execution" button in Labview (the icon with the lightbulb) and run your code to literally watch what happens in slow motion. This is a pretty handy debugging tool.