Tektronix FCA3000 Series, Руководство программиста

Страница: 177 / 191

Programming Examples
// Scan FORMat PACKed header.
if (*pBuf++ != '#') {
printf("Failed to scan packed header start\n");
WriteDev("abort");
Quit();
}
Digits = *pBuf++ - '0';
if (Digits < 1 || Digits > 9) {
printf("Failed to scan packed header size\n");
WriteDev("abort");
Quit();
}
int Size = 0;
for (i=0; i<Digits; i++) {
Size = 10 * Size + (int)(*pBuf++ - '0');
}
// With format packed and format:tinf on each sample is
// a double format measurement value and a 64 bit
// integer timestamp (in ps), for a total of
// 16 bytes / sample.
Samples = Size / 16;
for (i=0; i<Samples; i++) {
Val = *((double*)pBuf);
pBuf += 8;
if (i == 0 && _isnan(Val)) {
// Invalid value response.
printf("The instrument is apparently no longer measuring.\n");
Failed = true;
break;
}
TSVal = *((__int64*)pBuf);
pBuf += 8;
// Do something with the fetched result. For this
// test just check that the measurement result seems
// reasonable and that the timestamps increase as
// they should.
if (CheckMeas(Val, Args)) {
printf("Bad result of measurement %lf: %g %s\n", (double)Count, Val,
(Args.bPeriod ? "s" : "Hz"));
// Check that the timestamps keep increasing during
// the test run.
if (TSVal <= PrevTSVal) {
printf("Invalid timestamp, sample %lf, prev = %lf, Cur = %lf\n",
(double)Count, (double)PrevTSVal * 1e-12,
(double)TSVal * 1e-12);
}
// Check for gaps in the measurement data. This will
FCA3000, FCA3100, MCA3000 Series Programmer Manual 4-19