External signal aquisition rate

[WAtoMA]

Hello all,

I am trying to update a very old spectrometer to a digital interface. The signals coming from the instrument consist of two signals. One, is a constant analog pulse--which starts at a reference frequency (0) and then every pulse counts as another nanometer or wavenumber. The other signal varies from 0 to 100mV and represents the intensity (of the y-axis) at each respective wavenumber. I am trying to couple the two signals. The pulse signal (input PFI 0 / AI START) should tell the program when to sample the other, varying signal (currently not varying for testing purposes .22V) in input AI0 .

So the first pulse should represent wavenumber 0 and sample the other signal (at whatever variation it is in the respective range). The next pulse should represent wavenumber 1, and sample the other signal (at whatever variation it is in the respective range).....and so on.

I have both PCI-6251 and PCI-6220 boards. The Raman Spectrometer is an old 70's SPEX model.

I have attached my current program in progress.

When I hook up a function generator on a burst pulse sequence to the PFI 0 / AI START input in the Trigger / Counter section (100Hz) and a 9V battery with a resistor (.22V) to the AI 0 Input on my board,.....I get analog data starting to appear in my array, yet no graphing and no accompanying data in the Counter data 2 array.

What am I doing wrong? I am new to labview and am a chemist by trade.

Am I hooking up the signals correctly to the proper inputs?

Is my software code flawed?

Help please.

Real Raman VI 2.vi

[Anders Björk]

Hello all,

I am trying to update a very old spectrometer to a digital interface. The signals coming from the instrument consist of two signals. One, is a constant analog pulse--which starts at a reference frequency (0) and then every pulse counts as another nanometer or wavenumber. The other signal varies from 0 to 100mV and represents the intensity (of the y-axis) at each respective wavenumber. I am trying to couple the two signals. The pulse signal (input PFI 0 / AI START) should tell the program when to sample the other, varying signal (currently not varying for testing purposes .22V) in input AI0 .

So the first pulse should represent wavenumber 0 and sample the other signal (at whatever variation it is in the respective range). The next pulse should represent wavenumber 1, and sample the other signal (at whatever variation it is in the respective range).....and so on.

I have both PCI-6251 and PCI-6220 boards. The Raman Spectrometer is an old 70's SPEX model.

I have attached my current program in progress.

When I hook up a function generator on a burst pulse sequence to the PFI 0 / AI START input in the Trigger / Counter section (100Hz) and a 9V battery with a resistor (.22V) to the AI 0 Input on my board,.....I get analog data starting to appear in my array, yet no graphing and no accompanying data in the Counter data 2 array.

What am I doing wrong? I am new to labview and am a chemist by trade.

Am I hooking up the signals correctly to the proper inputs?

Is my software code flawed?

Help please.

LabVIEW is not that easy to learn, but the key is to make the problem into subproblems and thereafter merge these parts.

First have you logged the counter separately to see is there some time between each spectra (that is consistent)? In that case it would be fairly easy to collect both counter and voltage readings and build logic to extract your spectra. How long time does it take for the spectrometer to send a spectra?

Edited January 19, 2010 by Anders Björk