Mitsubishi Electric MELSEC-L LD75P User Manual page 401

Set a value in "[Da.8] Command speed" so that the speed of each axis does not exceed the "[Pr.8] Speed limit value". (The
speed limit does not function for the speed calculated by the LD75 during interpolation control.)
(3) 2-axis circular interpolation control with center point designation (INC circular
right, INC circular left)
(a) Operation chart
In the incremental system, 2-axis circular interpolation control with center point designation, positioning is
carried out from the current stop position (start point address) to a position at the end of the movement amount
set in " Da.6 Positioning address/movement amount" in an arc path having as its center the address (arc
address) of the center point set in " Da.7 Arc address".
Forward direction
Reverse
direction
Reverse
direction
Positioning of a complete round with a radius of the distance from the start point address to the arc center point
can be carried out by setting the movement amount to "0".
Reverese direction
In circular interpolation control with center point designation, an angular velocity is calculated on the
assumption that operation is carried out at a command speed on the arc using the radius calculated from the
start point address and center point address, and the radius is compensated in proportion to the angular
velocity deviated from that at the start point. Thus, when there is a difference (error) between a radius
calculated from the start point address and center point address (start point radius) and a radius calculated
from the end point address and center point address (end point radius), the composite speed differs from the
command speed as follows.
Start point address
(Current stop position)
Radius
Arc center point
(Arc address)
Movement amount to the end point
Forward direction
Arc center point
Reverese direction
CHAPTER 9 MAJOR POSITIONING CONTROL
Movement by circular interpolation
Movement amount
to the end point
Forward direction
(Arc address)
Movement amount = 0
Forward direction
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