VXi VT1422A 사용자 설명서

The most efficient means of acquiring algorithm derived data from the 
VT1422A is to have its algorithms store real-number results in the FIFO or 
CVT. The algorithms use the writefifo(), writecvt(), and writeboth() 
intrinsic functions to perform this operation as shown below.

Note that the first ten elements of the CVT are unavailable. These are used 
by the driver for internal data retrieval. However, all algorithms have access 
to the remaining 502 elements. Data is retrieved from the CVT with the 
SCPI command DATA:CVT? (@10,12,14:67)

For VXIplug&play Users: Use the function hpe1422_readCVT_Q for 
reading contiguous elements or hpe1422_cmdReal64Arr_Q(ViSession vi, 
’DATA:CVT? (@<element_list>)’, ViInt32 size, ViReal64 _VI_FAR 
result[ ], ViPInt32 count) for non-contiguous elements (as in the example 
above). See the VT1422A plug&play driver Help file.

The format of data coming from the CVT is determined by the FORMat 
command.

There is a fixed relationship between channel number and CVT element 
for values from channels placed in the Scan List with ROUT:SEQ:DEF. 
When mixing Scan List data acquisition with algorithm data storage, be 
careful not to overwrite Scan List generated values with algorithm generated 
values. See “ROUTe:SEQuence:DEFine” on page 323. for controlling CVT 
entries from the analog scan list.

CVT 10

Note: CVT 0 - 9 unavailable

writecvt( <expr>, 10 );

writecvt( <expr>, 13 );

writeboth( <expr>, 14 );

writefifo( <expr> );

CVT 11

CVT 12

CVT 13

CVT 14

CVT 511

(65,024 elements)

Current Value Table (CVT)

(502 elements)

First-in-First-Out Data Buffer (FIFO)