Count the delay time between two signals

[Water1]

Hello !
I use PCI-6115 to acquire two signals
One is excitation signal ,the other one is response signal.(see delay time.jpg)

Now my question is that how to count the delay time between two signals?

I also write two vi to count it ,but it seems that is difficult to count the delay time .

Who know where am I wrong ?

Thank you in advance !

[Water1]

two signals are spike train.

For delay time.jpg ,yellow signal is excitation signal, red signal is response signal.

[Omar_II]

Using DAQmx functions setup a task to acquire both signals and to trigger off the excitation signal.

Then the response waveform can be feed through the Basic Level Trigger Detection.vi and that will give you the time of the response. Depending on how you set up the trigger that time could be the delay you are looking for or you might have to subtract the trigger time of the excitation to get the delay.