VXI VT1422A - Manual (Page 177)

Advanced Programming with the VT1529B 175 Chapter 5
Temperature
Conversion
Sequence
Below is an example VXIplug&play command sequence. Note that this is
not executable; it has been simplified for easier reading. The C++ example
source file (tcpost.cpp) is on the CD supplied with the instrument. View the
readme.txt file provided with the VXIplug&play driver for example
program file location.
/* set up reference thermistor measurement
note that ch 10006 is excitation voltage, 10007 is thermistor voltage */
errStatus = hpe1422_cmd(vi, "sens:ref:post ther,5000,(@10006),(@10007)");
/* set function to temperature on channels 10000-10005 */
errStatus = hpe1422_cmd(vi, "sens:func:temp:post TC,J,(@10000:10005)");
/* associate TC channels with reference thermistor channel */
errStatus = hpe1422_cmd(vi, "sens:ref:chan:post (@10007),(@10000:10005)");
/* optionally set VT1529B input filters (2, 10 or 100 Hz) */
errStatus = hpe1422_cmd(vi, "inp:filt:freq 10,(@10000:10005)");
errStatus = hpe1422_cmd(vi, "inp:filt:stat on,(@10000:10005)");
/* set up the scan list to include the TC, thermistor and excitation channels */
errStatus = hpe1422_cmd(vi,"rout:seq:def (@10000:10007)");
/* set up the trigger system to make one scan for each trigger.
Note that the default is one scan per trigger and trigger source
is TIMer, so we only have to INITiate the trigger system to
take readings.
errStatus = hpe1422_cmd(vi,"trig:coun 1"); /* *RST default */
errStatus = hpe1422_cmd(vi,"trig:sour tim"); /* *RST default */
errStatus = hpe1422_cmd(vi,"arm:sour imm"); /* *RST default */
/* set up the sample timer. This controls the channel-to-channel scan
rate and can be important when channels need more than the default
40 us sample time. */
errStatus = hpe1422_cmd(vi,"samp:tim 40e-6"); /* *RST default */
/* INITiate the trigger system to execute a measurement scan */
errStatus = hpe1422_cmd(vi,"init:imm");
/* retrieve one scan’s data from the FIFO */
errStatus = hpe1422_readFifoPost_Q(vi, 1, 0, 65024, f64_array);
Voltage Measurements
With the VT1529B, low- or high-level dc voltage measurements can also be
made for sensors such as LVDT and string pots. While the VT1422A does
not provide built-in engineering units conversions for these sensor types,
custom EU conversions can be provided by the user.
Note
If a custom EU conversion is provided on a high-level dc voltage path, use
the SENSe:FUNCtion:CUSTom:HVOLtage command. Also see the
DIAGnostic:CUSTom:MXB command for specifying the custom
conversion parameters.