Omron FZ5 Series Hardware Setup Manual page 35

Term
2's complement
Vision System FZ5 series Hardware Setup Manual (Z423)
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) −"1" is expresses with 2's Complement (for 8 bits)
There are methods for simple calculation without performing this kind of computa-
tion.
For instance, "Negative number = inverting all bits of a positive number and then
adding 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 num-
bers can be used as is in calculations.
(Example) When −1+10=9
11111111 (= -1)
+)00001010 (= 10)
00001001 (= 9)
Definition
Terminology
33