Bitmapped versus Per-Resource VIs

There are two basic types of NI-Motion VIs—those that operate on one resource at a time, and those that operate on multiple axes, vector spaces, I/O bits, and so on simultaneously.

Per-resource VIs typically send numeric values to, or read numeric values from, the selected axis or resource. They operate identically on each axis or member in the resource family.

In contrast, VIs that operate on multiple bits send and return bitmaps, where each bit (axis, vector space, I/O bit, and so on) is represented by one bit in the bitmap.

Some VIs set and reset bits in the bitmap using the Must On/Must Off (MOMO) protocol. This tri-state protocol allows you to set/reset one or more bits without affecting the other bits in the bitmap. Refer to any of the MOMO VI descriptions for complete information about this protocol.

Bitmapped VIs act on all bits simultaneously. Because each execution reconfigures all bits in the bitmap, do not use these VIs incrementally.