HP 8168E - Page 128

6
Example 5 - Increased Tuning Linearity
if (argc != 2)
exit(-1);
sscanf(argv[1], "%lf", &theWvl);
return (SetExactWvl (theWvl));
}
/*-------------------------------------------------------------------------*/
int SetExactWvl (double theWvl)
/*-------------------------------------------------------------------------*/
{
/* open the instruments: */
INST laserSource = iopen("hpib,24"); /* laser source at hpib address 24 */
INST waveMeter = iopen("hpib,06"); /* wave meter at hpib address 6 */
int trialCnt;
int trialMax = 10;
double actWvl;
double diffWvlMax = 1.5e-12; /* 1.5 pm */
iprintf (laserSource, "WAVE %lg\n", theWvl); /* set the wavelength */
iprintf (laserSource, "OUTP ON\n"); /* turn the laser on */
for (trialCnt = 0; trialCnt < trialMax; trialCnt++)
{
actWvl = GetWavelength (waveMeter); /* read the wavelength */
if (fabs(actWvl - theWvl) < diffWvlMax) /* break if near enough */
break;
iprintf (laserSource, "WAVEACT %lg\n", actWvl);/* tell the laser source */
/* the actual wavelength */
}
iclose (laserSource); /* close the instruments */
iclose (waveMeter);
return trialCnt;
}
/*-------------------------------------------------------------------------*/
double GetWavelength (INST theInstrument)
/*-------------------------------------------------------------------------*/
{
double actualWvl;
6-18 Programming Examples