Mitsubishi Electric RD77MS2

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3 MAJOR POSITIONING CONTROL

3.2 Setting the Positioning Data

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".

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.

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 As compared with the speed without error, the speed becomes slower as end point address is reached.

Start point radius < End point radius As compared with the speed without error, the speed becomes faster as end point address is reached.

Radius

Movement by circular interpolation

Forward direction

Reverse direction

Reverse direction Forward direction

End point address

(positioning address)

Start point address

Arc center point

(Arc address)

(current stop position)