I use PXI6608 as counter, to measure the frequency of 50M, but always report error, seems have problem to get the frequency.
I use scope manually check, the waveform is there, just a little distortion in the peak, i guess this is not the case.
So i am not quite sure, need any additional setting, driver or config, the VIs works in another test station.
To be simple, if i have a square waveform, 1khz, and 50% duty, how to connect to the PXI 6608, and how to config, then i can manually check the frequency ?
1. Your second screenshot shows MAX test panels which only support pulse generation and edge counting. You can't directly measure frequency there. However, I'd still recommend you run the edge counting test to check out your wiring and signal compatibility.
You should be able to confirm that the count increases by ~1000 counts per sec. That lets you know that you have a proper signal wired correctly into the specified PFI pin.
2. Your first screenshot shows code that never explicitly designates where the frequency signal might be. DAQmx will make an assumption to use the default pin associated with freq measurement for the counter you configured. The other test station where the code works has probably wired the signal into that default pin.
You can either figure out what that default pin is (maybe CTR 1 Gate, based on seeing that you were using CTR 1 in the MAX screenshot) and physically move your wiring there or you can do some explicit configuration of your task to tell which PFI pin is actually wired up now (maybe PFI 32, based on seeing that in your MAX screenshot). You'd use a DAQmx Channel property node and it'd look like this:
3. I have personally almost always used the 1-counter method for frequency measurement. You might want to give that method a try as well. It should still give good resolution when measuring a 1 kHz signal.
Let's say if i want to run with my code, should connect the signal to pin 8(CTR1 GATE), then run the VI ?
Whether other kind of driver in NI-MAX is needed ?
I'm not sure why you refer to PFI 8 as CTR1 GATE. According to the pinout in the spec sheet, PFI 8 is CTR 7 OUT and PFI 34 is CTR1 GATE.
In the end, the physical wiring and the task configuration must match. Personally, I'd use my suggestion #2 above to define the task's PFI configuration *explicitly* and make it match the physical wiring.
Sorry, you did say *pin* 8, it was my mistake to think I was reading PFI 8.
Yes, it looks like pin 8 corresponds to PFI 34 which is also the default pin for CTR1 GATE. I'd expect that to work for the 1-counter freq measurement that I do, and I suspect it probably would work for the 2-counter freq measurement you're trying to do.
But it's possible the 2-counter freq measurement does things in a different way. That's why I think the safest approach is to designate the pin explicitly as I showed before with the property node for CI.Freq.Term.