NF FRA5097, Instruction Manual

Page: 135 / 192

6.3 File format
FRA5097 6-3
Table 6-1 shows both measurement data and setting conditions as binary files with file content
variables and size (number of bytes).
Table 6-1 Data types of variables within file
Types
Size
(number of bytes)
Notes
long 4 integer with sign
short 2 integer with sign
double 8 IEEE double precision floating-point number
float 4 IEEE single precision floating-point number
char
−
character type, 1 byte per character
The order of byte alignment is big-endian (higher order bytes are placed earlier according to the
order). Note that the byte alignment order is opposite to the data alignment order used for IBM
AT/PC compatible machines.
The following shows the formats of the IEEE double and single precision floating-numbers which
are used for the FRA5097 file.
„ Format of IEEE double precision floating-point number (8 bytes per data, or set of data)
Leading byte
seeeeeee eeeemmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm
| |
MSB MSB
s: sign of mantissa 0: positive, 1: negative
e: exponent (11 bits) exp: 0 - 2,047
m: mantissa (52 bits) mantissa
Numerical value = (
−
1)
s
×
2
(exp
−
1023)
×
(1+mantissa/2
52
)
where the number “1” that is underlined above should be eliminated when exp = 0.
„ IEEE single precision floating-point number (4 byte per data, or set of data)
Leading byte
seeeeeee emmmmmmm mmmmmmmm mmmmmmmm
| |
MSB MSB
s: sign of mantissa 0: positive, 1: negative
e: exponent (8 bits) exp: 0 - 255
m: mantissa (23 bits) mantissa
Numerical value = (
−
1)
s
×
2
(exp
−
127)
×
(1+mantissa/2
23
)
where the number “1” that is underlined above should be eliminated when exp = 0.