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.TH DDT "9" "2023-02-10" "LinuxCNC Documentation" "HAL Component"
.SH NAME

ddt \- Compute the derivative of the input function
.SH SYNOPSIS
.HP
.B loadrt ddt [count=\fIN\fB|names=\fIname1\fB[,\fIname2...\fB]]
.SH DESCRIPTION


For every function call from the real time thread, calculate the
difference between the old and current input value divided by the
timer elapsed since the last call.

.SH FUNCTIONS
.TP
\fBddt.\fIN\fB\fR (requires a floating-point thread)

.SH PINS
.TP
.B ddt.\fIN\fB.in\fR float in \fR
.br
.ns
.TP
.B ddt.\fIN\fB.out\fR float out \fR
.SH NOTES



As this only work on two consecutive input values, it will only work
well if the input change every function call, and not work so well if
the rate of change is very low and the input change do not happen
every time the real time function is called.


.SH AUTHOR

Jeff Epler
.SH LICENSE

GPL