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2308-900-01 Rev. A / July 2008 Return to Section Topics 10-5
Model 2308 Portable Device Battery/Charger Simulator User’s Manual Section 10: DISPlay and FORMat
Command notes (SCPI commands - data format)
FORMat[:DATA] <type> Select data format
Parameters <type> = ASCii ASCII format
SREal IEEE-754 single precision format
DREal IEEE-754 double precision format
This command is used to select the data format for transferring readings over the bus. The
reading(s) that is sent depends on the presently selected function (voltage, current, pulse-current,
DVM or long integration). See the
:FUNCtion command ( SENSe subsystem in Section 2 ) and
Measurement Commands and Optimizing Measurement Speed for more information.
ASCII format
The ASCII data format is in a direct readable form for the operator. Most Basic languages easily
convert ASCII mantissa and exponent to other formats. However, some speed is compromised to
accommodate the conversion. The following shows the ASCII format for a reading of 10.058 volts.
+1.00580000 E+01
IEEE-754 formats
SREal will select the binary IEEE-754 single precision data format. Figure 10-1 shows the normal
byte order format for each data element (voltage, current, etc.). 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. Not shown in
Figure 10-1 is a byte for the terminator that is attached to the end of each data
string.
Figure 10-1
IEEE-754 single precision data format
DREal selects the binary IEEE-754 double precision data format and is shown in
Figure 10-2 (normal byte order shown). This format is similar to the single precision format except
that it is 64 bits long.
NOTE
Regardless of which data format for output strings is selected, the power supply
will only respond to input commands using the ASCII format.
Byte 1
7 0
Header
# 0
Byte 2
7 0
Byte 3
7 0
Byte 4
s e 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.