09-27-2011 05:33 PM
Can anyone tell me how to make a Sample Clocked Buffered Frequency Measurement in a cDAQ chassis using NI-DAQmx with .NET 4.0?
I would like to make this type of measurement using a cDAQ chassis (with a DI module) and synchronize it with AI measurements from other modules in the chassis.
The User Manual for the cDAQ-917x chassis indicates that this is a supported measurement option but I can't find any program examples or other support for implementing it.
If I create a frequency measurement in NI-MAX for a cDAQ chassis, it is not one of the measurement types provided in the drop down list.
In addition, I cannot find any reference to this method anywhere in the NI-DAQmx .NET assembly nor find any reference to the CI.Freq.EnableAveraging property which apparently can be used to control the buffer averaging.
My .NET NI-DAQmx Assembly version: 9.3.40.219.
Thanks,
09-28-2011 07:27 PM
Hey Jeff,
Can you respond with the DAQ card that you're going to be using?
Thanks,
09-29-2011 08:17 AM
cDAQ NI-9411
09-30-2011 04:22 PM
Hi Jeff,
The NI-9411 that you're using should be compatible with this kind of measurement. There is an example that ships with Measurement Studio that makes a Sample Clocked Buffered Frequency Measurement, which should be found on your computer at: C:\Users\Public\Documents\National Instruments\NI-DAQ\Examples\DotNET4.0\Counter\Measure Digital Frequency\MeasDigFreqBuffCont_ExtClk_ArmStart\VB. This example is written in VB, and there should be a C# example at the same path as well.
To configure this kind of frequency measurement in NI-MAX, you just need to go to the Advanced Timing tab, and set the Timing Type to "Sample Clock."
Best,
Dan Nelson
Applications Engineer