TECHNICAL NOTE
MOTION APPLICATION ENGINEERING GROUP
Yaskawa Electric America - 2121 Norman Drive South – Waukegan IL 60085
(800) YASKAWA - Fax (847) 887-7280
11/23/2005 45 of 45 eng/05.055/MCD
Handling Rollover
Use the math functions ADDX or SUBX to prevent miscalculations due to long registers, ML or
DL rollover. With 32 bit registers, the maximum and minimum decimal values are
+2,147,488,647 and –2,147,488,648, which correspond to 7FFF FFFF and 8000 0000 in Hex
respectively. For example, if IL8016 has rolled over from the positive or the negative side, the
IL8016 and ML00100 math would be as follows:
Positive Rollover: –2,147,488,000 – (+2,147,488,000) = +1296
Negative Rollover: (+2,147,488,000 – (–2,147,488,000) = -1296
Using ADDX and SUBX always guarantees that the result of the math operation is a valid
answer, and no error will be generated.
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