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MELSEC-Q
9 MAJOR POSITIONING CONTROL
In circular interpolation control with center point designation, an ang ular velocity is
calculated on the assumption that operation is carried out at a com mand 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 f rom the start
point address and center point address (start point radius) and a radius c alculated
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 followin g 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" com binations are possible.)
•When "reference axis speed" is set in " Pr.20 Interpolation speed
designation method"
(2) An error will occur and the positioning start will not be possible in the foll owing
cases. The machine will immediately stop if the error is detected dur ing
positioning control.
•When the radius exceeds "536870912 (=229)". (The maximum radius for
which circular interpolation control is poss ible 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 c enter 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 -231 to 231-1
... A "Center point setting error" (error code: 527) will occur.