VXI VT1422A - Manual (Page 306)

304 VT1422A Command Reference Chapter 7
MEASure
MEASure
The MEASure subsystem provides convenient setup-and-execution for some
pre-measurement strain operations.
Subsystem Syntax MEASure
:VOLTage
:EXCitation (@<ch_list>)
:UNSTrained (@<ch_list>)
MEASure:VOLTage:EXCitation?
MEASure:VOLTage:EXCitation? (@<ch_list>) This command automatically
configures the VT1422A to measure the bridge excitation voltage at each channel in
<ch_list> and starts a measurement scan. It averages 32 measurements for each
channel and the averaged values are stored internally for later use by the strain
Engineering Unit Conversion process. The average of each channel’s reading is also
sent to the FIFO buffer for use in user defined conversion processes. The command
returns a single value which is the number of readings sent to the FIFO.
Note
The maximum excitation voltage the VT1422A can sense through the
VT1529A/B’s excitation sense path is 16 volts (±8 V dc centered about the Gnd
terminal). If a higher excitation voltage is supplied through the VT1529A/B, don’t
connect the excitation sense terminals.
Note that this command executes a measurement scan without executing any
algorithms that might be defined.
The sequence of individual commands to approximate this operation is
TRIGger:COUNt 1
one time through scan list
ROUTe:SEQuence:DEFine (@<ch_list>)
input the list of channels to measure
SENSe:FUNCtion:VOLTage [<range>,](@<ch_list>) set measurement function to volts
SENSe:STRain:EXCitation:STATE ON,(@<ch_list>) turn on excitation supplies
SENSe:STRain:CONNect EXCite,(@<ch_list>)
connect channel sense to excitation
supply
INIT
start measurement scan
SENSe:DATA:FIFO:COUNT?
query for number of readings in FIFO
enter statement here to return FIFO reading <count>
SENSe:DATA:FIFO:PART? <count>
read excitation values from the FIFO
enter statement to for block data from FIFO
next the excitation voltage values acquired above must be sent back to the VT1422A by
executing the following command once for each channel in <ch_list> above:
SENSe:STRain:EXCitation <voltage_value>,(@<channel>)