86 Digitizers Command Reference Chapter 3
Comments Readings Returned in Interleaved Configuration: The readings are returned in
an array in an interleaved configuration. That is, the array contains the first
reading from each specified channel followed by the second reading from
each specified channel. The readings are in channel number order starting
with the lowest to highest specified channel in the channel list. For example,
the channel list (@2,1) returns channel 1 readings followed by channel 2
readings and returns the same as channel list (@1,2).
NOTE Measurement data on channels not in the specified channel list are
discarded by this command and is not recoverable. This command can
read the data from a measurement only once. It is a destructive read and
the data cannot be retrieved a second time.
Number of Readings Returned: The number of readings this command will
return for each channel is determined by the number of samples set by
SAMPle:COUNt. The total number of readings returned is the number of
samples times the number of specified channels. If a measurement is
aborted with the ABORt command, there may be less readings available
than indicated by (samples x channels). For ABORted measurements,
use DATA:COUNt? to determine how many readings are available.
Overloads and Deadlocks: A full scale reading may actually be an overload.
A deadlock can occur when trigger events are set to BUS or HOLD because
a software trigger could not break in after this command is sent.
PACKed Data Format: Data are returned as raw data (16-bit integers) when
the data format is set to PACKed (see FORMat[:DATA] PACKed). To
convert the raw readings to voltages, use voltage = reading * range/32768
or use voltage = reading * resolution (use [SENSe:]VOLTage[:DC]:
RESolution? to obtain the resolution value).
REAL Data Format: Data are returned as real numbers when the data format
is set to REAL (see FORMat[:DATA] REAL). The data is returned in voltage
units and no scaling conversion is required as with the PACKed format.
Readings are in an interleaved configuration.
IEEE-488.2 Headers: Both PACKed and REAL formats return data preceded
by the IEEE-488.2 definite length arbitrary block header. The header is #
<num_digits> <num_bytes>, where
• # signifies a block transfer
• <num_digits> is a single digit (1 through 9) which specifies how
many digits (ASCII characters) are in <num_bytes>
• <num_bytes> is the number of data bytes which immediately
follow the <num_bytes> field.
Executable when initiated: YES
Coupled command: NO
Reset (*RST) condition: none