Omron FH-1 series User Manual page 13

Term
2's complement
Vision System FH/FHV/FZ5 Series User's Manual (Z365)
Binary numbers are generally used to represent negative numbers.
Negative numbers are expressed by "Inverting all bits of a positive number and adding
1 to the result".
(Example) "−1" is expressed as 2's complement
"−1" can be calculated by "0-1".
(In the case of 1, minus 1)
00000000 (= 0)
− )
00000001 (= 1)
11111111 (=−1)
There are methods for simple calculation without performing this kind of computation.
For instance, "Negative number = inverting all bits of a positive number and then add-
ing 1 to the result".
00000001 (= 1)
Invert all bits
11111110
Plus 1
11111111 (=−1)
The first digit is used to judge whether the number is positive or negative.
When 0: Positive number (or 0)
When 1: Negative number
The advantage of two's complement numbers is that positive and negative numbers
can be used as is in calculations.
(Example) When −1+10=9
1 1111111 (= −1)
+)00001010 (= 10)
00001001 (= 9)
Definitions of Basic Terms
Definition
−"1" is expresses with 2's Complement (for 8 bits)
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