Delta RMC101 User Manual
Page 206
RMC100 and RMCWin User Manual
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These issues prompted the introduction of Enhanced curves.
Enhanced Curves
Enhanced curves were introduced with RMC CPU firmware dated 20010208. They greatly enhance
the capabilities of the RMC in following an arbitrary curve, and further enhance the smoothness of the
curve.
The following items are introduced with enhanced curves:
• The accelerations at the endpoints of a curve are always zero (0). Therefore, there is no
acceleration discontinuity and therefore much lower jerk at the end points. The acceleration is
continuous over the entire curve, even with the additional features listed below.
• Segments can be easily designated as linear segments, which makes them exactly linear. This
greatly simplifies camming and flying cut-off applications.
• Any point, including the endpoints, can have its velocity set to a specific value. This, too,
simplifies camming and flying cut-off applications.
• Curves can be set up to auto-repeat, meaning that the curve restarts automatically when it
reaches its end. See Auto Repeat Curves for details.
The drawback of Enhanced curves is that they can currently only be downloaded to the RMC through
RMCWin's Curve Tool, and not from a Programmable Controller through communication modules
such as Ethernet, PROFIBUS, and Modbus Plus. See Curve Tool Overview for details on the Curve
Tool.
You should always use Enhanced curves unless you are running firmware prior to 20010208 and do
not wish to upgrade, or you need to download curves through the communication module.
What If I Don't Want Zero Velocity at My Endpoints?
Each spline segment in a Standard curve will begin and end at zero velocity. This is desirable so
that when a motion controller's axis is given the command to follow a spline curve, the axis does
not instantly jerk to the new velocity. However, there are applications where the curve does not
begin with zero velocity.
If the curve is downloaded from RMCWin, then you can switch to use an Enhanced curve which
allows the velocity of each point to be set. However, if the curve is being downloaded over
Ethernet, Modbus Plus, PROFIBUS or some other communication module, it is recommended
that the user add one or more points to the beginning and end of the curve. The following curves
demonstrate how this can be done: