Derivative x(t) PtByPt VI

Owning Palette: Integral & Differential PtByPt VIs

Requires: Full Development System

Performs a discrete differentiation on x.

This VI is similar to the Derivative x(t) VI.

Note  By default, reentrant execution is enabled in all Point By Point VIs.

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	initialize, when TRUE, initializes the internal state of the VI.
	x is an input data point.
	initial condition is the value used to calculate the derivative for the first and second point. The default is 0.
	dt is the sampling interval and must be greater than zero. The default is 1.0. If dt is less than or equal to zero, the VI returns an error.
	dx/dt is the differentiated data point.
	error returns any error or warning from the VI. You can wire error to the Error Cluster From Error Code VI to convert the error code or warning into an error cluster.

Derivative x(t) PtByPt Details

This VI uses the 2nd Order Central method to calculate the differentiation. Let y represent the output dx/dt. y is given by the following equations:

y₀ = (x₀ – initial condition)/2dt

y₁ = (x₁ – initial condition)/2dt

y_j = (x_j+1 – x_j–1) / 2dt, for j = 2, 3, 4, …

where y_j is the output dx/dt of the (j+1)^th call of this VI and x_j is the input x of the (j+1)^th call of this VI.