Keithley 2302 User Manual

11-6 DISPlay, FORMat, and SYSTem
DREal selects the binary IEEE-754 double precision data format and is shown in
Figure 11-2 (normal byte order shown). This format is similar to the single precision format
except that it is 64 bits long.
Figure 11-2
IEEE-754 double precision data format
Byte 1
70
Header Byte 2
70
Byte 7
70
Byte 8
70
se f
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.
# 0
During binary transfers, never un-talk the power supply until after the data is read (input) to
the computer
. Also, to avoid erratic operation, the readings of the data string (and terminator)
should be acquired in one piece. The header (#0) can be read separately before the rest of the
string.
The number of bytes to be transfe
rred can be calculated as follows:
Bytes = 2 + (Rdgs ×
4) + 1 for SREAL
Bytes = 2 + (Rdgs ×
8) + 1 for DREAL
where: 2 is the number of bytes for the header (#0).
Rdgs is the number of readings to be transferred.
4 or 8 is the number of bytes for each reading.
1 is the byte for the terminator.
For example, assume that the power supply is configured to trigger 10 voltage readings and
se
nd the 10 voltage measurements to the computer using the binary format.
Bytes = 2 + (10 × 4) + 1
= 43 for SREAL
Bytes = 2 + (10 × 8) + 1
= 83 for DREAL
FORMat:BORDer <name> Specify binary byte order
Parameters <name> = NORMal
Normal byte order for binary formats
SWAPped Reverse byte order for binary formats
This command is used to control the byte order for the IEEE-754 binary formats. For normal
b
yte order, the data format for each element is sent as follows:
Byte 1 Byte 2Byte 3Byte 4 (Single precision)
Byte 1 Byte 2• • • Byte 8 (Double precision)
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Keithley 2302 Specifications

General

Brand	Keithley
Model	2302
Category	Power Supply
Language	English