Ocean Opics USB2000+ labview synchronizing sampling with external hardware trigger

[Jackeyyuxi]

Hi all,

Now I am using a USB2000+ spectrometer to contiously get spectrum in a Labview 'while loop' program. I use the 'get_spectrum.vi' to read the spectrum each time. The spectrometer is triggered by an external hardware trigger with repirition rate of 1kHz and pulse duration of ~800ns. Normally the intergration time is set 40-100ms.

After reading each spectrum, the Labview will also analyze the spectrum and save the spectrum to hard disk of computer. Normally this will take less than 25ms.

But now, I got a problem. I found sometimes the 'get_spectrum.vi' fail to get the correct spectrum but something wrong (some constant values). This means, at these times, the program fail to get the correct spectrum.

Is it possible that the 'get_spectrum.vi' fail to get the spectrum because the intergration of the spectrum is not finished by the spectrometer ? Or the external hardware trigger is too fast ?

 I also tried to decrease the external hardware trigger to 25Hz. Under this condition, the intergration time of the spectrometer has to be set at 40ms (if other intergration time is set, the spectrum read mismatch will be more severe). Also, under this condition, there will be a spectrum wavelength sudden shifting sometimes. It seems the spectrum is not fully read. I am really confused. Attached please find the labview program figure.

In addition, I am using Labview 8.6 and the OmniDriver version is Labview 7.1 or 8.5. Will this cause some problem ?

Thank you very much !

Yuxi