Keithley 2001 - IEEE754 Single Precision Data Format (32 Data Bits); IEEE754 Double Precision Data Format (64 Data Bits)

IEEE-488 Reference
4-87
REAL,64 or DREal will select the binary IEEE754 double precision data format and is shown
in Figure 4-21 (normal byte order shown). This format is similar to the single precision format
except that it is 64 bits long.
F
igure 4-20
I
EEE754 single precision data format (32 data bits)
Byte 1
70
Header
# 0
Byte 2
70
Byte 3
70
Byte 4
70
se f
s = sign bit (0 = positive, 1 = negative)
e = exponent bits (8)
f = fraction bits (23)
Normal byte order shown. For swapped byte order,
bytes sent in reverse order: Header, Byte 4, Byte 3,
Byte 2, Byte 1.
The Header is only sent once for each measurement conversion.
Byte 1
70
Header Byte 2
70
Byte 7
70
Byte 8
70
se f
# 0
F
igure 4-21
I
EEE754 double precision data format (64 data bits)
s = sign bit (0 = positive, 1 = negative)
e = exponent bits (11)
f = fraction bits (52)
Normal byte order shown. For swapped byte order,
bytes sent in reverse order: Header, Byte 8,
Byte 7 .... Byte 1.
The Header is only sent once for each measurement conversion.
Bytes 3, 4, 5, and 6 not shown.