Omron SYSMAC CV Series Operation Manual page 50

Data Area Structure
Decimal Points
Signed and Unsigned Data
Unsigned binary
Digit value
Bit number
Contents
Signed Binary
Sign indicator
Digit value
Bit number
Contents
38
Because the numeric equivalent of each four BCD binary bits must be nu-
merically equivalent to a decimal value, any four bit combination numerically
greater than 9 cannot be used, e.g., 1011 is not allowed because it is numeri-
cally equivalent to 11, which cannot be expressed as a single digit in decimal
notation. The binary bits 1011 are of course allowed in hexadecimal and are
equivalent to the hexadecimal digit B.
There are instructions provided to convert data between BCD and hexadeci-
mal. Refer to 5-15 Data Conversion for details. Tables of binary equivalents
to hexadecimal and BCD digits are provided in the appendices for reference.
Decimal points are used in timers only. The least significant digit represents
tenths of a second. All arithmetic instructions operate on integers only. When
inputting data for use by Special I/O Units or other special applications, be
sure to check on the type of data required for the application.
This section explains signed and unsigned binary data formats. Three instruc-
tions, MAX(165), MIN(166), and SUM(167), can use either signed or unsigned
data.
Unsigned binary is the standard format used in OMRON PCs. Data in this manu-
al are unsigned unless otherwise stated. Unsigned binary values are always
positive and range from 0 ($0000) to 65,535 ($FFFF). Eight-digit values range
from 0 ($0000 0000) to 4,294,967,295 ($FFFF FFFF).
3
16
15 14 13 12 11
0 0 0 0 0
Signed binary data can have either a positive and negative value. The sign is
indicated by the status of bit 15. If bit 15 is OFF, the number is positive and if bit 15
is ON, the number is negative. Positive signed binary values range from 0
($0000) to 32,767 ($7FFF), and negative signed binary values range from
–32,768 ($8000) to –1 ($FFFF).
3
16
15 14 13 12 11
0 0 0 0 0
Eight-digit positive values range from 0 ($0000 0000) to 2,147,483,647 ($7FFF
FFFF), and eight-digit negative values range from –2,147,483,648 ($8000
0000) to –1 ($FFFF FFFF).
2
16 16
10 09 08 07 06
0 0 0 0 0
2
16 16
10 09 08 07 06
0 0 0 0 0
Section 3-2
1 0
16
05 04 03 02 01
0 0 0 0 0
1 0
16
05 04 03 02 01
0 0 0 0 0
00
0
00
0