Here, I have two questions.
1.
I use a DAQ NI 6341 to count the edges of the TTL pulses sent by an APD (pulse width 17 ns). It works well. But I still want to know which parameter of the NI 6341 determine the minimum pulse width that it can count properly? And what is the minimum pulse width that the NI 6341 can count properly?
2.
I write a program for the continuous buffered edge counting. In my program, I create a digital output of continuous waveform format and use its “DO Sample Clock (100KHz)” as the gate signal of the counter. In the part of the continuous buffered edge counting, I choose the “DO Sample Clock” as the “Source” of “Sample Clock VI” and then use a function generator to send TTL pulses (pulse width 30ns) to test my program.
First, I set the "rate" of the "DAQmx Timing VI" as "1MHz" and send TTL signals with repetition rate "1MHz" to NI 6341, and the incremental value of counter read by "DAQmx Read" is "10" as my expect.
Second, I set the "rate" of the "DAQmx Timing VI" as "10KHz" and send TTL signals with repetition rate "1MHz" to NI 6341, and the incremental value of counter read by "DAQmx Read" is also "10". It hard for me to figure out this result.
I discuss this issue with the NI engineer of Taiwan. He told me that the function of “DAQmx Timing VI” here is analogous to the “DAQmx Timing VI” of the analogy input. If his words were right, the incremental value of counter read by "DAQmx Read" should be 100.
I also test other values for the “rate”. The incremental value of counter read by "DAQmx Read" is always "10".
Could anyone explain for me why this happens?