Single and Double-Buffered Parameters

Almost all NI-Motion parameters are either single-buffered or double-buffered on the controller. Single-buffered parameters take effect immediately upon function execution and remain in effect until they are overwritten with another call to the function that loaded or set them. It is not necessary to constantly reload single-buffered parameters each time you deal with an axis, vector space, or resource. The obvious exception to this is action commands like Start Motion, Stop Motion, and so on, which must be called each time.

Most trajectory control parameters are double-buffered. You can load these parameters on the fly without affecting the move in process. They do not take effect until the next Start or Blend Motion function is executed. Like single-buffered parameters, the controller retains the values so they do not have to be loaded before each move unless you want to change their values.

Load Breakpoint Position and Load Breakpoint Modulus are the only non-trajectory parameters that are also double-buffered. They have no effect until you execute a subsequent Enable Breakpoint Output function.