Ieee754 Single Precision Data Format (32 Data Bits); Ieee754 Double Precision Data Format (64 Data Bits); Scpi Command Reference - Keithley 2000 User Manual

Figure 5-2
IEEE754 single
precision data
format (32 data
bits)
Figure 5-3
IEEE754 double
precision data
format (64 data
bits)
SREAL will select the binary IEEE754 single precision data format. Figure
5-2 shows the normal byte order format for each data element. For example,
if three valid elements are specified, the data string for each reading conver-
sion 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 equiva-
lent of an ASCII # sign and 0.
Header Byte 1
# 0
7 0 7
s e
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.
DREAL selects the binary IEEE754 double precision data format and is
shown in Figure 5-3 (normal byte order shown). This format is similar to the
single precision format except that it is 64 bits long.
Header Byte 1
# 0
7 0 7
s e
Bytes 3, 4, 5, and 6 not shown.
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.

SCPI Command Reference

Byte 2 Byte 3
0 7
f
Byte 2 Byte 7
0 7
f
5-29
Byte 4
0 7 0
Byte 8
0 7 0