Delta RMC101 - Manual (Page 685)

Appendix A: Command Reference
A-33
The Spline Relative Sine Move (w) command parameters are defined as follows:
Command
Parameter
Description
Mode The superimposed and gear bits must be set.
Acceleration Time/Distance Select: If the Speed parameter is zero, this
parameter specifies the time for this move to complete.
Deceleration Spline Position: Specifies the position of the leftmost point
of the spline. This effectively shifts the spline right or left as
viewed on the curve tool, providing a starting point other
than the default of zero.
Speed Master Move Distance: The sine move occurs as the master
moves this distance. If this parameter is zero, the sine move
will be based on time. Note that this value can be negative.
Command
Value
Offset: This is the distance the slave must move from the
spline.
Why Bother?
This command can be used to transition from one spline to the next if the start and end points are
not the same. This command can also be used when changing splines on the fly. If this command
is issued while already following a spline, it will move to the specified offset to the new spline.
To carry out his command, the RMC performs the following steps:
1. First the RMC calculates where to index into the spline table. This is done by using the master
axes current position and subtracting the DECEL field to get the X index in the curve tool. For
example, if the master is at 500 position units and the minimum position (DECEL field) is 400
position units, the X index would be 100 position units. NOTE: Never let the master position go
below the minimum or maximum positions!
2. The RMC uses the X index (or master position) to interpolate a position from the spline to find the
Y position (spline position).
3. The Command Value (spline offset) is added to the Y position to get the destination to where the
slave must move.
4. The relative distance between the slave’s destination and current position is calculated.
5. The speed field determines how the sine move is executed as a function of the change in the
master's position.
6. The slave now initializes two target generators. One calculates the current spline position as a
function of the master's X index. The other starts the sine move that will move the relative
distance calculated in step 4. The resulting speeds and differences in position are summed to
make a smooth move that converges at the offset from the spline.
7. Once the axis position has reached the offset spline position, the axis will continue to follow the
spline at the offset given the Command Value.