NI 73xx Velocity Override in Percent
The Load Velocity Override VI or function takes a single-precision floating-point (f32) data value from 0 to 150%, but velocity override is internally implemented as a velocity scale factor of 0 to 384 with an implicit fixed denominator of 256. NI-Motion uses the velocity override to increase the speed of the calculation for the sake of calculation speed—the division is a shift right by eight bits. The resolution for velocity override is therefore limited to 1/256, or about 0.39%.
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Note The conversion from floating-point to fixed-point is performed on the host computer, not on the motion controller. To load velocity override from an onboard variable, you must use the integer representation of 0 to 384, where 384 corresponds to 150%. |
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Note If the distance of the move is too small, it may not be possible to reach the commanded maximum move constraints. In such instances, NI-Motion adjusts the move constraints lower to reach the commanded position. |