Omron CVM1D, Operation Manual

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91
The following example shows the bit status of CIO 0000 as
“0011110000001110.” This would be represented as “3C0E” in hexadecimal.
Bit 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
ON/OFF 0 0 1 1 1 1 0 0 0 0 0 0 1 1 1 0
2
3
2
2
2
1
2
0
2
3
2
2
2
1
2
0
2
3
2
2
2
1
2
0
2
3
2
2
2
1
2
0
2
1
+ 2
0
= 3 2
3
+ 2
2
=12 0 2
3
+ 2
2
+2
1
=14
Digit 3 C 0 E
With unsigned binary data, the digits expressed in hexadecimal can be con-
verted to decimal by multiplying the value of each digit by its respective factor.
For example, the hexadecimal value “3C0E” would be converted as follows:
(3 x 16
3
) + (12 x 16
2
) + (0 x 16
1
) + (14 x 16
0
) = 15,374
The range that can be expressed in hexadecimal 0000 to FFFF (i.e., 0 to 65,535
decimal).
Two-word data is handled as 32-bit binary data. Values can be expressed as
eight-digit hexadecimal (0000 0000 to FFFF FFFF), and the equivalent decimal
range is 0 to 4,294,967,295.
4-12-2 Signed Binary Data
Data is configured in words, with 16 bits per word. This data is regarded as 16-bit
binary data, with the leftmost bit (i.e., the most significant bit, or MSB) used as
the sign bit. Signed binary data is often written as four digits hexadecimal.
When the leftmost bit is OFF, (i.e., set to 0), the number is positive and the value
is expressed as four-digit hexadecimal, from 0000 to 7FFF.
When the leftmost bit is ON, (i.e., set to 1), the number is negative. The value is
expressed as four-digit hexadecimal, from 8000 to FFFF, in 2’s complement.
Because the leftmost bit is used as the sign bit, the absolute value that can be
expressed is less than that for unsigned binary data.
With signed binary data, the status of the sign bit (i.e., the MSB) determines
whether the number will be positive or negative. When the sign bit is OFF, the
number will be either positive or zero. As with unsigned binary data, the value
can be converted to decimal by multiplying the value of each digit by its respec-
tive factor. For example, the hexadecimal value “258C” would be converted as
follows:
(2 x 16
3
) + (5 x 16
2
) + (8 x 16
1
) + (12 x 16
0
) = +9,612
Conversion to Decimal
Range of Expression
Double Data
Conversion to Decimal
Data Formats
Section 4-12