Mitsubishi Electric MELSEC iQ-F Series FX5 User Manual page 129

Circular interpolation error compensation
In the circular interpolation control with the center point specification, the arc path calculated with the start point address and
center point address and the end point address set in [Da.6] Positioning address/movement amount may deviate. (Page
398 [Pr.41] Allowable circular interpolation error width)
■Calculated error ≤ [Pr.41] Allowable circular interpolation error width
The circular interpolation control to the set end point address is performed, while the error compensation is performed. (This
operation is called spiral interpolation.)
Path according to spiral interpolation
Start address Center point address
In the circular interpolation control with the center point specified, an angular velocity is calculated with an assumption that the
positioning target moves at the command speed on the arc using the radius calculated from the start point address and center
point address. The radius is compensated in proportion to the angular velocity moved from the start point.
Thus, if a difference (error) is found between a radius (start point radius) calculated from the start point address and center
point address and a radius (end point radius) calculated from the end point address and center point address, the composite
speed differs from the command speed and as described below.
Error between start point radius
and end point radius
Start point radius > End point radius
Start point radius < End point radius
■Calculated error ≥ [Pr.41] Allowable circular interpolation error width
Large arc error deviation (Error code: 1A17H) occurs at the start of the positioning and the control will not start.
During the positioning control, the operation stops immediately at the detection of the error.
Error
End address according to calculation
End point address
Composite speed
Compared with the speed without an error, the speed becomes slower as the end point address is reached.
Compared with the speed without an error, the speed becomes faster as the end point address is reached.
9 MAJOR POSITIONING CONTROL
9.2 Positioning Data Settings
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