Delta RMC151 - Manual (Page 162)

RMC70/150 and RMCTools User Manual
Finally, the curve object itself will require 20xN+144 bytes or 200,144 bytes. Therefore,
the Curve Store must have 40,048 + 160,064 + 200,144 or 400,256 bytes available to
successfully download this curve. Notice however, that after the curve has been added,
the re-assembly and computation buffers will be freed up, leaving only 200,144 bytes
used for this curve from the Curve Store.
Example 2
How much Curve Store memory is used to add fifty (50) Cubic Curves with Zero-Velocity
Endpoints—each with 10,000 points—to the RMC75E using the Curve Tool?
When downloading a curve using the Curve Tool, each download will require a Download
Buffer of 16 bytes per point plus curve name and description length plus 40 bytes. If we
assume that each curve’s name and description use 20 characters total, then each
10,000-point Cubic curve will require a download 160,060 bytes. The Computation Buffer
and Curve Object will have the same sizes as calculated in Example 1, 160,064 bytes and
200,144 bytes respectively.
When each curve is downloaded, the Download Buffer will be allocated, then the Curve
Object, and finally the Computation Buffer. Once the curve is successfully added, the
Download and Computation Buffers will be freed up, leaving only the Curve Object in the
Curve Store. Each of the 50 curves is downloaded in this manner. Therefore, the
approximate total Curve Store memory requirement for 50 of these curves is 50 Curve
Objects, 1 Download Buffer, and 1 Computation Buffer, which is ( 200,144 x 50 ) +
160,060 + 160,064 = 10,327,324 bytes or 9.8 MB. Notice that this exceeds the 8MB
Curve Store capacity available on the RMC75E. Therefore, these curves cannot be
downloaded to this controller.
Fragmentation of the Curve Store Memory
After adding and deleting curves, the Curve Store memory may become fragmented,
limiting the memory available for adding curves. To clear the memory completely, use the
Curve Delete All (85) command.
3.6.7.9. Example: Creating a Curve using the Curve Add
Command
This topic gives a simple example of how to create a curve using the Curve Add (82) command
and the variable table. For more details on curves, see the Curves Overview and Curve Tool
topics.
This procedure is for curves small enough to fit in the Variable Table, and the points are
spaced evenly on the X-axis (or time axis). It can be used for position, pressure, or force, and
can be used for a time-based curve or a master-based curve.
This example will create an example curve with nine points. The X-axis (or time axis) points
are evenly spaced, and the end points have zero velocity (the axis will be stopped at the
ends).
1. Determine the Curve Points
Determine the distance or time between points on the X-axis (or time axis), and
determine each point on the Y-axis. This example will use a time between points of
0.25, and nine Y-axis points as shown below:
X-axis (time) 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00
Y-axis 1.0 2.0 2.1 2.2 2.0 1.7 1.9 1.3 1.6
142 Delta Computer Systems, Inc.