User manual
IEEE-488 Reference
3-80
REAL,32 or SREal will select the binary IEEE754 single precision data format. Figure 3-19
shows the normal byte order format for each data element. For example, if three valid elements
are speciļ¬ed, the data string for each reading conversion is made up of three 32-bit data blocks.
Note that the data string for each reading conversion is preceded by a 2-byte header that is the
binary equivalent of an ASCII # sign and 0.
REAL,64 or DREal selects the binary IEEE754 double precision data format and is shown in
Figure 3-20 (normal byte order shown). This format is similar to the single precision format
except that it is 64 bits long.
Figure 3-19
IEEE754 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.