PCI 6602 event counting and autocorrelation with DAQ assistant

[RoxZ]

I am using 7.1 Labview and a PCI-6602 counter to count photons. Everytime a photon is detected I have a comparator set up to give a pulse out. I wish to count the number of pulses and then graph their autocorrelation. I have been told to use the DAQ assistant to simply count the number of events first. But I thought it would be better to use the Create Channel.VI for the counter and read the task from there,using another counter as the gate. I have tried hooking this up looking at the Count Digital Events example but it times out at the Wait Until Done.vi without detecting any pulses.I can't work out where it has gone wrong. Should I just hardware time the DAQ assistant and start afresh working with that?

Also attempting to graph any autocorrelation,even with a simulated signal,is proving difficult. I have been told I might have to time stamp the pulses coming in and graph the autocorrelation that way. Does anyone know where I can read more on using the Autocorrelation function?

[Seamus_C]

Hi RoxZ

I would suggest placing down a DAQmx task constant.  Click on the down arrow and select browse.  Then select Create new to open your Daq Assistant.  Once you have configured your Daq Assistant, right click on the task constant and select generate code, example.

You will have an output from your DAQmx Read Vi.  This will show your count.  You can also use this out put for your Autocorrelation VI.  Place the Autocorrelation VI outside the while loop, wire to it, right click the data tunnel on the while loop and enable indexing.  Connect this to the X input of the Autocorrelation VI.

See the following links for information on the Autocorrelation VI

http://zone.ni.com/reference/en-XX/help/371361A-01/lvanls/autocorrelation/

http://zone.ni.com/reference/en-XX/help/lv/71/lvanls

Hope this helps,

Seamus