Omron SYSMAC CV Series Operation Manual page 118

Data Formats
Range of Expression
Double Data
Correlation Between Binary
Data and Decimal Numbers
106
When the sign bit is ON, on the other hand, the number will be negative, and the
method for converting to decimal will be different. Because the value is ex-
pressed in 2's complement, it must first be converted to a negative number and
then the value of each digit can be multiplied by its respective factor. For exam-
ple,the hexadecimal value "CFC7" would be converted as follows:
2's complement
True value (negative)
The negative decimal number is then calculated as follows:
3
–[(3 x 16 ) + (0 x 16
Note To convert a negative decimal number into signed binary data, follow the above
procedure in reverse. In other words, first convert the absolute value into 2's
complement, then reverse the bits and add one.
The hexadecimal range is 0000 to 7FFF for a positive number and 8000 to FFFF
for a negative number. These are equivalent in decimal to 0 to +32,767 for a posi-
tive number and -32,768 to -1 for a negative number.
Two-word data is handled as 32 bits of binary data, with the leftmost bit of the
leftmost word used as the sign bit. Values can be expressed as eight-digit hexa-
decimal (0000 0000 to 7FFF FFFF, 8000 0000 to FFFF FFFF), and the equiva-
lent decimal range is 0 to +2,147,483,647 (positive) and –1 to –2,147,483,648
(negative).
Unsigned binary data
FFFF
FFFE
etc.
8001
8000
7FFF
7FFE
etc.
0002
0001
0000
Cannot be expressed.
C F C
1100 1111 1100
C F C
1100 1111 1100
3 0 3
0011 0000 0011
2 1 0
) + (3 x 16 ) + (9 x 16 )] = –12,345
Decimal number
+65,535
+65,534
etc.
+32,769
+32,768
+32,767
+32,766
etc.
+2
+1
0
-1
-2
etc.
-32,767
-32,768
Section 4-13
7
0111
Subtract 1.
6
0110
Reverse the status of each bit.
9
1001
Signed binary data
Cannot be expressed.
7FFF
7FFE
etc.
0002
0001
0000
FFFF
FFFE
etc.
8001
8000