IDEC MICRO/I HG4G-CJT22 F-B Series User Manual page 34

1 WindO/I-NV4 Specifications
Data type
bit
Upper word
31
BCD8(EB)
Sign
Data is handled as a 32-bit floating-point real number. The number of significant digits is 6 digits. The
floating-point type data format conforms to the IEEE (The Institute of Electrical and Electronics Engineers)
standard for the single precision storage format as explained next.
Single precision floating-point values in IEEE 754 (32 bits)
Single precision floating-point values in IEEE 754 are expressed with a total of 32 bits (2 words) using 1 bit for
the sign s, 8 bits for the exponent e, and 23 bits for the significand f. The sign bit indicates the sign of the
expressed value (positive or negative). The exponent is an 8 bit signed integer with a value from -128 to 127.
bit
31
s
Float32(F)
Sign bit (0: positive, 1: negative)
Example:
s
0 0 1 1 1 1 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
If all bits are 0, the value is "0".
The internal representation of Float32(F) is described here, but the data for Float32(F) (floating-point real
numbers) is handled with a special bit configuration, so do not directly access the bits.
Data type
The entered text are stored in the upper byte and the lower byte according to the Storage Method of
String Data setting of WindO/I-NV4.
Select the from Upper byte in the Storage Method of String Data
1st
character
Upper byte
Float32(F)
Select the from Lower byte in the Storage Method of String Data
2nd
character
Upper byte
For details, refer to Chapter 10 "2.6 String Data Storage Method" on page 10-55.
The Storage Method of String Data is configured on the System tab in the Project Settings dialog
box.
2-2
Lower word
7th 6th 5th 4th 3rd 2nd 1st
Absolute value
bit
30
e (exponent) [bit 30 to 23]
+127
e
- 2
1 . 1 × 2
String Data
1 word
2nd 3rd
character character
Lower byte Upper byte
String Data
1 word
1st 4th
character character
Lower byte Upper byte
WindO/I-NV4 User's Manual
Data handling
Data is handled as an eight digit (32-bit) binary-coded decimal
bit
value.
0
Each four bits from bit 0 to bit 27 is handled as the absolute value
for the 1st to 7th digit.
Bit 28 to bit 31 is handled as the minus sign (-) when its value is F
(Hex) and it is handled as the absolute value for the 8th digit when
0 to 9 (Hex).
bit bit
23 22
f (significand) [bit 22 to 0]
Represents after the decimal of 1.xxx
f
Data handling
n-2-th n-1-th n-th
character character character
Upper byte Lower byte Upper byte
NULL
n-1-th n-2-th
(00 ｈ )
character character
Upper byte Lower byte Upper byte
NULL
(00 ｈ )
Lower byte
n-th
character
Lower byte
bit
0