MITSUBISHI ELECTRIC Mitsubishi Programmable Logic Controller QD75D - Manual (Page 496)

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MELSEC-Q
12 CONTROL SUB FUNCTIONS
(3) When continuous path control of a circular interpolation is being carried out in
the near pass, an address in which the extra movement amount is subtracted
from the positioning address of the positioning data currently being executed is
replaced by the starting point address of the next positioning data No.
Because the starting point address will be replaced, an error "Large arc error
deviation" (error code: 506) may occur.
In this case, adjust the " Pr.41 Allowable circular interpolation error width".
Address designated by positioning data No.1
Path of positioning
address pass
Positioning data No.2
Positioning data No.1
Positioning data No.2
starting point address
during the near pass
Path of near pass
Fig. 12.12 Arc error during the near pass
(4) When a circle center is designated to continuously designate the circular
interpolation control by a continuous path designation in the near pass, and
the positioning address and starting point address of that arc are the same
address, the path will make one circle using the two data items. This is
because the 2nd data starting point address is shifted by the extra amount of
the movement amount occurring from the 1st data.
Path of positioning data No.1
Starting point address of positioning data No.1
Starting point address of
positioning data No.2
Path of positioning data No.2
[Near pass]
Example