랩뷰 샘플레이트 지정 문의

[pbs0730]

안녕하세요, DAQ기기를 통해 가속도 센서, 엔코더, 힘 센서 데이터를 수집하고 LabVIEW를 통해 이를 처리하는 프로그램을 작성하고 있습니다.
기존에 sample rate를 3000Hz로 사용하고 있었는데, 같은 시간 축에 대해서 가속도 신호가 엔코더, 힘 신호와 어긋나는 것을 확인했습니다.
이를 해결할 방법을 찾던 중, sample rate를 1600, 3200 혹은 1024, 2048, 4096 (8192는 주기가 빨라서 그런지 어긋났습니다)Hz로 설정하였을 때, 시간 축이 어긋나지 않음을 확인할 수 있었습니다. 이와 관련한 정보가 있는지 여쭤봅니다.

[GerdW]

Hi pbs,

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@pbs0730 wrote:

Hello, I'm developing a program that acquires acceleration, encoder, and force sensor data using a DAQ device and processes it in LabVIEW.
I was previously using a sample rate of 3000Hz, but I noticed that the acceleration signal was misaligned with the encoder and force signals over the same time axis.
While researching a solution, I found that setting the sample rate to 1600, 3200, or 1024, 2048, or 4096Hz (8192Hz showed a misalignment, likely due to its fast cycle) eliminated the time axis misalignment. Could you please provide some information regarding this?

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All we can say is:

• there's a problem in your code
• you don't use the right DAQ hardware for your task

Which kind of help do you expect when you don't provide any substantial information?

[dsb@NI]

PBS:

Misalignment could be interpreted different ways. Are your signals not start synchronized with each other? Or,  are the signals drifting (in time) with respect to each other?

For start synchronization,  make sure acquisitions use same start trigger. Also,  make sure that you account for different delays (analog and digital) delays on your channels. If you are using DSA devices to measure acceleration and force,  these have substantially more delay than MIO devices. 

For clock synchronization between different modules,  consult DAQmx synchronization examples. If you have access to Sound and Vibration Toolkit,  it ships with several examples that implement synchronization between acquisition of vibration signals and analog tachometers and between acquisition of vibration signals and digital tachometers.

And Gerd is absolutely right that we can be more helpful when you provide more details and... CODE!

[pbs0730]

First of all, thank you for your reply, and I found out that it is decided for the internal filter and internal master timing base of NI 9230 block, so I resolved it. Thank you again.