Mitsubishi Electronics QD75P, QD75D user manual Restrictions

9 MAJOR POSITIONING CONTROL

MELSEC-Q

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.

Restrictions

(1) 2-axis circular interpolation control cannot be set in the following cases.

•When "degree" is set in "

Pr.1

Unit setting"

•When the units set in "

Pr.1

Unit setting" are different for the reference axis

and interpolation axis. ("mm" and "inch" combinations are possible.)

•When "reference axis speed" is set in " designation method"

Pr.20

Interpolation speed

(2)An error will occur and the positioning start will not be possible in the following cases. The machine will immediately stop if the error is detected during positioning control.

•When the radius exceeds "536870912 (=229)". (The maximum radius for which circular interpolation control is possible is "536870912 (=229)"

... An error "Outside radius range " (error code: 544) will occur at positioning start.

•When the start point address is the same as the center point address

... A "Center point setting error" (error code: 527) will occur.

•When the end point address is the same as the center point address

... A "Center point setting error" (error code: 527) will occur.

•When the center point address is outside the range of -231to 231-1

... A "Center point setting error" (error code: 527) will occur.

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