Delta RMC101 - Manual (Page 208)

RMC100 and RMCWin User Manual
4-22
Clear Spline Segments This is used to clear one or more segments from the motion controller's
memory.
Follow Spline Segment This causes the axis to follow a single spline segment. The motion controller
updates the spline every millisecond. The axis must already be at the
position of the first point for this command to succeed.
Follow Spline Relative This causes the axis to follow a single spline segment relative to the current axis
position. This command is similar to the Follow Spline (f) command but
does not require the axis to be at the position of the first spline point.
In addition to these five commands, there are two other ways to download splines. They are
described under Downloading Splines to the RMC. When using other methods of download
splines—using the Spline Download Area and using RMCWin—the first three commands listed
above are not used, but the final two still apply.
A Cubic Spline Example
Suppose that a cant (a section of a log) is scanned for a curve sawing application. For simplicity,
we assume the cant was scanned at only seven points. We also assume that we're using a
Sensor Digital I/O to keep track of the quadrature counter on the belt moving the cant. Therefore,
we'll also assume that the cant was scanned at a uniform distance between readings of 200
quadrature counts.
Therefore, suppose the optimizer gave the following readings:
Counts
Since Start
of Cant
Position of Saws (in
thousandths of inches)
0 60000
200 61000
400 61500
600 61250
800 61000
1000 60750
1200 61000
In this application it is not safe to assume that the saws should be at zero velocity at the ends of
the cant. Therefore, we'll use one of the methods described above for getting non-zero velocities
at the ends: we will add a point to the beginning and end of these sets of points. So the new data
will look like this:
Counts
Since Start
of Cant Position of Saws (in
thousandths of inches)