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NI-6602 Two Channel Frequency Measurement using Traditional NI-DAQ and LabView 8.2

I have been trying to program for some new experiments and have a vi setup to record the time-of-arrival for a signal using buffered event counting on two channels.  We really wanted to be able to measure the frequency of the incoming photons on both channels and thought we could just make a sub vi using simple event counting and count the number of rising edges on a source pin for a second and report that number and repeat the measurement until we were done..

All of our vi's have to be programed using the Traditional NI-DAQ drivers as the NI-DAQmx drivers do not play well with the FIFO overwrites on the 6602 card that occasionally occur in our measurements (high instantaneous count rates from bursts of photons).  The way other groups using the 6602 card and labview have dealt with this is to ignore the error that come from the Read Buffer.vi used with the Traditional NI-DAQ drivers when a FIFO overwrite occurs.  Trying this same technique with the NI-DAQmx drivers has not worked so we are stuck with the old drivers.

With this all said I made a vi that counted the freqency on one counter just fine but when I adapted it for two channels it doesn't like me anymore 😞

I attached the llb file and any comments would be greatly appreciated

-Shane
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Hello Sprice,

Browse the shipping examples according to “Directory Structure” and then select DAQ to find the Traditional DAQ examples.  There a lot of examples that are written for counters (Counter >> daq-stc.llb >> Count Edges (DAQ-STC).vi). 

What kind of signals are your photons creating?  Are they TTL compatible at a certain frequency?  You don’t care about overwriting your buffer?

Respectfully,

Rob F
Test Engineer
Condition Measurements
National Instruments
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Thanks Rob I'll have to take a look at thos examples I hadn't tried looking accouding to directory structure.  I did finally figure out this afternoon what I was doing wrong with the vi that I posted previously so that is working as well.
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