Yaskawa LEGEND-MC - Manual (Page 275)

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LEGEND-MC User’s Manual
Specifying Vector Speed for Each Segment
The instruction VS has an immediate effect and, therefore, must be given at the required time. In some
applications, such as CNC, it is necessary to attach various speeds to different motion segments. This can
be done with two functions: < n and > m
For example:LI x < n >m
The first command, < n, is equivalent to commanding VSn at the start of the given segment and will
cause an acceleration toward the new commanded speed, subject to the other constraints.
The second function, > m, requires the vector speed to reach the value m at the end of the segment. Note
that the function > m may start the deceleration within the given segment or during previous segments, as
needed to meet the final speed requirement, under the given values of VA and VD.
Note, however, that the controller works with one > m command at a time. As a consequence, one
function may be masked by another. For example, if the function >100000 is followed by >5000, and the
distance for deceleration is not sufficient, the second condition will not be met. The controller will
attempt to lower the speed to 5000.
As an example, consider the following program.
Changing Feedrate:
The command VR n allows the feedrate, VS, to be scaled between 0 and 10 with a resolution of .0001.
This command takes effect immediately and causes VS to be scaled. VR also applies when the vector
speed is specified with the ‘<’ operator. This is a useful feature for feedrate override. VR does not ratio
Instruction Interpretation
#ALT Label for alternative program
DP 0,0 Define Position of X and Y axis to be 0
LMX Define linear mode.
LI 4000 <4000 >1000 Specify first linear segment with a vector speed of 4000 and
end speed 1000
LI 1000 < 4000 >1000 Specify second linear segment with a vector speed of 4000
and end speed 1000
LI 0 < 4000 >1000 Specify third linear segment with a vector speed of 4000 and
end speed 1000
LE End linear segments
BGS Begin motion sequence
EN Program end