VXI VT1422A, User Manual

Page: 295 / 529

VT1422A Command Reference 293 Chapter 7
FORMat
FORMat
The FORMat subsystem provides commands to set and query the response data
format of readings returned using the [SENSe:]DATA:FIFO:
…
? commands.
Subsystem Syntax
FORMat
[:DATA] <format>[,<size>]
[:DATA]?
FORMat[:DATA]
FORMat[:DATA] <
format
>[,<
size
>]
sets the format for data returned using the
[SENSe:]DATA:FIFO:
…
?, [SENSe:]DATA:CVTable and FETCh? commands.
Parameters
Comments
•
The REAL format is IEEE-754 Floating Point representation.
•
REAL, 32 provides the highest data transfer performance since no format
conversion step is placed between reading and returning the data. The default
<size> for the REAL format is 32 bits. Also see DIAG:IEEE command.
•
PACKed, 64 returns the same values as REAL, 64 except for Not-a-Number
(NaN), IEEE +INF and IEEE -INF. The NaN, IEEE +INF and IEEE -INF values
returned by PACKed,64 are in a form compatible with Workstation BASIC and
BASIC/UX (see table on following page).
•
REAL 32, REAL 64, and PACK 64, readings are returned in the IEEE-488.2-1987
Arbitrary Block Data format. The Block Data may be either Definite Length or
Indefinite Length depending on the data query command executed. These data
return formats are explained in “Arbitrary Block Program and Response Data”
on page 233. For REAL 32, readings are 4 bytes in length (data type is
float32
array ). For REAL 64 and PACK, 64, readings are 8 bytes in length (data type
is float64 array ).
•
ASCii is the default format. ASCII readings are returned in the form
±
1.234567E
±
123. For example 13.325 volts would be +1.3001.
Each reading is followed by a comma (,). A line feed (LF) and End-Or-Identify
(EOI) follow the last reading (data type is
string array ).
Parameter
Name
Parameter
Type
Range of
Values
Default
Units
format discrete (string) REAL | ASCii | PACKed none
size numeric for ASCii, 7
for REAL, 32 | 64
for PACKed, 64
none