Please judge on my understanding about the while loop timing problem. I think the analog signal is running at 100Hz precisely, but the while loop is running faster, if no timing is specified. So when the trigger detection is checking the value more often than usual, if the value is greater or equal than 2 then it gives a true value, otherwise it gives a false. That is the reason I am getting more than 100 triggers without a wait(ms) vi.
When I put in the wait vi, and specify 10ms to wait, the trigger detection is running at the same period of the signal. So it will check whether the signal is above zero at 0s, 0.01s, 0.02s, ...1s. So I can get the right number of total triggers in 1 sec. But it seems that because I did not make the counts increase one when the Time has Elapsed is true, my counts of triggers will not be right. Therefore I add one more frame before averaging. And the results turns out to be right.
The forging successful result is based on the assumption that I know the frequency of the signal, so I can check the trigger at the same frequency. But the data in my experiment is of a different type. I have the impulses, but the frequency is not known and it is changing with time. So I need to modify the vi again to account for the frequency variation. I think there are two ways to do it. One is modify the trigger detection function to make it ouput the rising edge only, The other is having the trigger detection run much faster than the square waves, which is event I want to measure, and then using the trigger location to mark the even with lots of points. Then I should be able to mark the point at the end of low signal and the beginning of high signal. So I change the location mode into Time. But this rising edge is still dependent on the choice of the ms to wait function. Do you have any idea on this?
