PCI 6225

[paulak]

Hi everyone,

I am trying to read 35 signals (coming from 35 photodiode array pixels) one after another. For this, I heard I could use a PCIcard 6225 with 80 analog input channels. Would I be able though to link the 35 signals coming out of each pixel to a terminal (BNC or screw terminal...)? If yes what should I use to connect these 35 signals?

In my application, the photodiode will be on a XY stage. To record the signal coming out of one particular pixel, the photodiode will be moved, then the signal recorded. The photodiode will be moved to another position, the signal recorded...etc.

If someone can give me some advice that would be nice,

Thanks

[WM_John_Weeks]

Sounds like you don't need 35 inputs to the DAQ device. Since it is a single photodiode taking readings at each of 35 positions serially, just do a 35-sample scan. Hopefully you have signals available from the XY stage telling you when the photodiode is in position and ready to be read. Use that signal as the scan clock.

[AnalogKid2DigitalMan]

Do you plan on using signal conditioning circuitry to boost the electrical output of the photodiode to a level that DAQ card can readily acquire (100's of mV or Volts)? Just a suggestion.

[paulak]

Thanks to both of you,

On the photodiode array, there will be a scintillating crystal array, for which we want to test light output uniformity. As suggested John, there are 2 solutions:

- I could fix the crystal over the photodiode array and move the photodiode array under the crystal. But I would loose some signal due to crystal/photodiode interface.

- I could fix the crystal onto the photodiode array and multiplex the 35 signals coming out of the 35 phd pixels. I would trigger data acquisition for a fixed position of the XY stage. At the moment I have a DAQPad 6052E and a BNC 2090 so I have only 16 analog input channels available.

I will also need to amplify signal with a charge amplifier. So if I use the second solution I will need to have some circuitry after the photodiode.

Cheers,

[WM_John_Weeks]

Ah. It's a photodiode *array*. That's different.

Can you get along with reading just 16 of the 35 outputs, carefully choosing which ones to read?

Otherwise, I can't see how you're going to do it without adding some more hardware. At least a multiplexer, like a SCXI module, which would defeat the advantages of the DAQCard device.

[paulak]

Hello,

No, I will have to read all 35 channels.

Would I need SCXI chassis + multiplexer module? Do you know if I can use this SCXI device along with my DAQPad-6052E for data acquisition?

Regards,