Omron SYSMAC CP Series, Руководство пользователя

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4-21
4 Understanding Programming
CP2E CPU Unit Software User’s Manual(W614)
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* Data range for single-precision floating-point decimal: - 3 .402 8 2 3 × 10
38
≤
Value
≤
-1.175494 × 10
- 38
, 0, +1.175494 ×
10
- 38
≤
Value
≤
3 .402 8 2 3 × 10
38
Type Data format
Decimal
equivalent
4-digit
hexadeci-
mal
BCD (binary
coded deci-
mal) #0 to #9999 #0000 to
#9999
Single-preci-
sion floating-
point decimal
This format conforms to the IEEE 754 standard for single-precision floating-
point data. It is used only with instructions that convert or calculate floating-
point data.
• Input using operands in the CX-Programmer as signed decimal or 3 2-bit
hexadecimal with the # symbol.
• When inputting operands in the I/O Memory Edit/Monitor Window of the CX-
Programmer as signed decimal values with seven digits or less, the value will
be automatically converted to scientific notation (mantissa× 10
Exponent
) for
setting and monitoring. Inputs must be made using scientific notation for val-
ues with eight or more digits.
Example: When -12
3 4.00 is input, it will become -1.2 3 4000e+00 3 in scientific
notation. For the mantissa×10
Exponent
, the value before the e is the man-
tissa and the value after the e is the signed exponent.
*
−
2
3
2
2
2
1
2
0
BCD
→
Decimal
→
15 14 13 12 11 10 9 8 7 6 5 4 3 2 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
0 to 9 0 to 9 0 to 9 0 to 9
Sign of
mantissa Exponent Mantissa
Val u e = (-1)
sign
×1.[Mantissa] × 2
Exponent
· Sign b it ( b it 31): 1: N egati v e, 0: Positi v e
· Mantissa: The 23 b its from b it 00 to b it 22 contain the mantissa, i.e., the portion
b elo w the decimal point in 1. .....,in b inary.
Indicates this v al u e.
30 31 29 23 21 22 20 19 2 1 0
Binary
· The 8 b its from b it 23 to b it 30 contain the exponent. The exponent
is expressed in b inary as the n in 2
n
. The act u al v al u e is 2
n-127
.