NI-USB 6009 triggering problems

[9554466]

Hello,

I'm using a program that uses NI-USB 6009 and external generator. Usb gets value from detector on generators impulse falling edge (USB is triggered via generator). 

Problem:

Generator frequency does gets up to 1MHz. USB takes values till ~100kHz, if we get higher it starts to take random unknown values from the detector (making up values). I am tracking pulses from detector via osciloscope also.

I would appriciate any suggestion that would fix this problem.

[0utlaw]

Hello 9554466,

It's not 100% clear what you're trying to do with the 6009 (are you attempting to do hardware-triggered single point acquisition?), but the specifications for that DAQ clearly state that the maximum analog sampling rate is 48 KSamples/sec.  I'm not surprised that you're seeing erroneous data when attempting to force the device to operate beyond that limit.

Regards,

[9554466]

Is it possible for device to wait till he will get next sample available on a trigger?

[0utlaw]

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@9554466 wrote:

Is it possible for device to wait till he will get next sample available on a trigger?

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This question is very vague and the terminology you're using is ambiguous.  Without more information about what you are attempting to do and what you've already done, there isn't much more advice we can give you. 

Please post the code you're attempting to use as well as a clear description of your hardware setup and what specific issues (errors, screenshots of results) you are trying to troubleshoot.

Regards,

[9554466]

Hello,

well the same problem still remains but I do have another question. 

Just started testing out the NI-USB with external generator. I use 2 channels from impulse generator (X1 and X2). X1 connected to NI-USB trigger input (PFI 0, GND), X2 connected to analog input (ai3).

Adjusted impulse generators frequency to 10kHz. X1 (trigger from falling edge) impulse width 700ns , X2 (data) impulse width 700ns.

While changing the delay of second (X2) channel I tried to find maximum value on the indicator in Trigger.vi program (attached). The delay between signals were 2.1us. And data that was shown in waveform chart graph was scattered (Image attached).

Should I get data like that on my wave chart, if not, how do I fix it? And should the delay between trigger and actual signal be this huge?

[ConnorM]

Good Day

One problem that I see with the code you attached and the speed of your application is that you are using a DAQ Assistant. I would suggest working with examples that come with LabVIEW. Go to the Help menu » Find Examples..

and select Hardware Inputs and Outputs » DAQmx » Analog Input and select an example that fits your application.

Also you are at the fastest you can sample from two channels (23-24 kHz). That is a delay of 45-42 mirco seconds between measurements. Your pulses width of 700ns is far too small of the USB 6009 to read.

-Connor M