jom012265

Thanks - I'm actually programming in LabVIEW, and I'm using the 'ULx Read (Counter U32 1CHan 1Samp).vi' when in a loop and 'ULx Read (Counter U32 1CHan NSamp).vi' when doing a finite sample count single data-batch grab.

OK, so the 96MHz is basically a base-clock. I'm trying to identify the difference between the sample rate input by the user (in your example 100 Hz), which seems to be a polling rate, and the sample rate at which the signal is sampled. For example if I input that 100Hz as a sample rate, and in between two consecutive reads (that were 1/100 sec apart) the signal had 3 pulses that were for example 10usec long each, I assume the count would be 3 when the last read returns, but in order to catch those three 10usec pulses, the rate at which the 3 pulse-signal was sampled would have to be at least 200kHz correct? How does the device know how fast the this raw signal has to be sampled?...or am I missing something?

In the specifications for the CTR04, the 'Timebase' is listed as 96MHz. Am I correct in assuming that this is the basic sampling freuquency, i.e. the frequency that the fpga samples the raw input signal coming in on an input channel with? I assume this based on the fact that the specified 'Maximum input frequency', i.e. what I assume is the max frequency of the raw signal wired into a Ci port, is listed as 48MHz, i.e. the frequency one would get based on the Nyquist '1/2' criteria - 96/2 = 48. Likewise, is the 'Counter read pacer' basically the polling rate, i.e. the 'rate' input to the ULx Timing (Sample Clock) LabVIEW vi? So for example if this polling rate is 2Hz (e.g. twice a second), the count returned by each call of the ULx Read... LabVIEW vi would be the number of raw signal pulses that occured inbetween last two polling instances (assuming the 'clear after read' was set to True)?