Mitsubishi Electric RD77MS2 User Manual page 93

2-axis circular interpolation control with center point designation (ABS circular)
■Operation chart
In the absolute system, 2-axis circular interpolation control with center point designation positioning is carried out from the
current stop position (start point address) to the address (end point address) 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 from the start point address to the arc center point can be carried out by setting
the end point address (positioning address) to the same address as the start point address.
Forward direction
Reverse direction
Reverse 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 radius > End point radius
Start point radius < End point radius
Movement by circular interpolation
Start point address
(current stop position)
Radius
Arc center point
(Arc address)
Arc center point
(Arc address)
Start point address
(current stop position)
Forward direction
As compared with the speed without error, the speed becomes slower as end point address is reached.
As compared with the speed without error, the speed becomes faster as end point address is reached.
End point address
(positioning address)
Forward direction
End point address
=
(positioning address)
3 MAJOR POSITIONING CONTROL
3.2 Setting the Positioning Data
3
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