Experiences of using NI USB 6210 for photon counting

[hanh]

Dear friends

I am using NI USB6210 and a photon counting unit C9744 (Hamamatsu) for my photon counting system.

C9744 output : TTL, 10ns, prescaler 1,10.

My VI : LabVIEW8.0, DAQ Assistant (acquire signal, counter/frequency measurement....)

The problem is : how to  set up of VI  in order to measure highest frequency input from C9744.

My VI set up : two counter, high freq. , time : 10m,  one sample.... and the maximum frequency I can measure is 800kHz???

I ask for your experiences in this problem.

Thanks

[samantham]

Hello,

For High Frequency 2 Counter Method, it is best to select a long Measurement Time in comparison to the signal that is being measured.  Please refer to the image below to see how the 2 counter method is laid out.  The larger the frequency difference between the paired counter output and the frequency to be measured, the more accurate the measurement.  The paired counter output / known period is the input for Measurement Time, where you have it set to 10 ms.  What is the range of high frequencies you are attempting to measure?  Are you trying to measure a frequency of 800 k or is this a limiting frequency that you are seeing?

I realize you are using the DAQ Assistant, however have you tried using one of the examples that ship with LabVIEW.  In the Example Finder under the Help Menu, there is an example titled Meas Dig Frequency-Buffered-Cont-High Freq 2 Ctr.vi that is located in the Browse tab under the <Hardware Input & Output> <DAQmx> <Counter Measurements> <Digital Frequency> folders.