34
1 OVERVIEW
1.2 Data Specification Method
Real number data (floating-point data)
Data size and data range
Real number data includes single-precision 32-bit real number data.
Real number data can be stored only in devices other than bit devices or in single-precision real data type labels.
Configuration of single-precision real number data
Single-precision real number data consists of a sign, mantissa, and exponent, and is expressed as shown below.
The following figure shows the bit configuration of the internal expression of single-precision real number data and the
meaning of each part.
■
Sign (1 bit)
This bit represents the positive or negative sign of a numerical value. "0" indicates a positive number or 0. "1" Indicates a
negative number.
■
Mantissa (23 bits)
A mantissa means XXXXX
of 1.XXXXX
2
N
representing a single-precision real number in binary.
■
Exponent (8 bits)
An exponent means N of 1.XXXXX
2
N
representing a single-precision real number in binary. The following table shows the
relationships between the exponent value and N of a single-precision real number.
Precautions
■
When setting an input value of single-precision real number from the engineering tool
The number of significant digits is about 7 because the engineering tool processes single precision real number data in 32-bit
single precision.
When the input value of single-precision real number data exceeds 7 digits, the 8th digit is rounded off.
Therefore, if the rounded-off value goes out of the range from -2147483648 to 2147483647, it will not be an intended value.
Ex.
When "2147483647" is set as an input value, it is handled as "2147484000" because 8th digit "6" is rounded off.
Ex.
When "E1.1754943562" is set as an input value, it is handled as "E1.175494" because 8th digit "3" is rounded off.
Data name
Data size
Value range
Single-precision real number data (single-precision
floating-point data)
Positive
number
32 bits (2 word)
2
-126
real number<2
128
Zero
0
Negative
number
-2
128
<real number
-2
-126
Exponent (b24 to b30)
FFH
FEH
FDH
81H
80H
7FH
7EH
02H
01H
00H
N
Not used
127
126
2
1
0
-1
-125
-126
Not used
1.
× 2
Mantissa
Sign
Exponent
b31
b30
∙∙∙
b23
b22
b16
∙∙∙
b15
b0
∙∙∙
Sign
Exponent
Mantissa
Содержание MELSEC iQ-F FX5
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Страница 24: ...22 MEMO ...
Страница 25: ...23 PART 1 PART 1 OVERVIEW Part 1 consists of the following chapter 1 OVERVIEW 2 PRECAUTIONS ON PROGRAMMING ...
Страница 126: ...124 6 SEQUENCE INSTRUCTIONS 6 3 Output Instructions Operation error There is no operation error ...
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Страница 140: ...138 6 SEQUENCE INSTRUCTIONS 6 3 Output Instructions Operation error There is no operation error ...
Страница 191: ...7 BASIC INSTRUCTIONS 7 2 Arithmetic Operation Instructions 189 7 Operation error There is no operation error ...
Страница 202: ...200 7 BASIC INSTRUCTIONS 7 2 Arithmetic Operation Instructions Operation error There is no operation error ...
Страница 278: ...276 7 BASIC INSTRUCTIONS 7 4 Bit Processing Instructions Operation error There is no operation error ...
Страница 280: ...278 7 BASIC INSTRUCTIONS 7 4 Bit Processing Instructions Operation error There is no operation error ...
Страница 915: ...18 TYPE CONVERSION FUNCTIONS 18 13 Converting DWORD to WORD 913 18 Operation error There is no operation error ...
Страница 917: ...18 TYPE CONVERSION FUNCTIONS 18 14 Converting DWORD to INT 915 18 Operation error There is no operation error ...
Страница 932: ...930 18 TYPE CONVERSION FUNCTIONS 18 26 Converting DINT to WORD Operation error There is no operation error ...
Страница 1050: ...1048 26 TIME DATA FUNCTIONS 26 4 Division MEMO ...
Страница 1068: ...1066 29 COUNTER FUNCTION BLOCKS 29 4 Counter Function Block Operation error There is no error ...
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