NI DAQ Assistant - error removal while acquiring data

[Sudhan_mp]

Hello all,

I'm trying to acquire vibration data using DAQ assistant. From some books and journals, we found that the zero output should be removed from the output reading to get accurate results. Is it necessary to remove zero output? If yes, how to do it? What is the purpose of error in and error out in DAQ assistant? Can we do this zero output correction in DAQ assistant itself?

Kindly share your suggestions

[GerdW]

Hi Sudhan,

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@Sudhan_mp wrote:

I'm trying to acquire vibration data using DAQ assistant.

What is the purpose of error in and error out in DAQ assistant?

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Which DAQ devices do you use?

Which sensor do you use?

Which LabVIEW version do you use?

Why do you want to use the (limited) DAQAssistent when there are DAQmx functions available?

The errorIO for DAQAssistent provides the same functionalities as for any other LabVIEW function with "standard errorIO behaviour"! (That citation is a hint to read the LabVIEW help…)

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@Sudhan_mp wrote:

From some books and journals, we found that the zero output should be removed from the output reading to get accurate results. Is it necessary to remove zero output? If yes, how to do it?

Can we do this zero output correction in DAQ assistant itself?

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That feature often is called "taring"/"tare" - and there are a lot of threads in this board about "how to implement a zeroing/taring feature": please look up those threads on your own.

• It is only necessary when you need good measurement accuracy: in your example the zero value would result in 10% error…
• As said before: the DAQAssistent is quite limited so it cannot implement a taring function on its own…

[Sudhan_mp]

Hi GerdW,

Greetings for the day!!!

Thank you for your kind reply. Please find the answers below.

Which DAQ devices do you use? cDAQ -9178 and USB 4431

Which sensor do you use? IEPE Accelerometers and Microphones

Which LabVIEW version do you use? LabVIEW 2023 Q1

Why do you want to use the (limited) DAQAssistent when there are DAQmx functions available? Not much aware about DAQmx functions. We are using DAQ Assistant since most tutorials use it.

[Bob_Schor]

You should (almost) always use the Error Line -- it's built into the functions that NI "builds it into" and until you know and understand LabVIEW better, you should (almost always) use it.

You should (as quickly as possible) wean yourself from the "crutch" of the Dreaded DAQ Assistant (and "almost never" use its Evil Twin, the Dynamic Data Wire).  Do a Web Search for "Learn 10 Functions in NI-DAQmx and Handle 80 Percent of your Data Acquisition Applications" (skip Chapter 1, which says "Use the DAQ Assistant").  I'm beginning to think that the DAQ Assistant was created for NI Customer Reps who, a decade or more ago, used to show up at Universities to give 1 hour Demo's of LabVIEW for Engineering Students and showing them how quickly they could get "data" using the DAQ Assistant.  Better was a 2 hour lab I devised for some BME students to create a "Touch Sensor" using a USB-6009 (it also used a  resistor, 1 Mohm, I think) -- when the code was running and the student touched a wire connected to one pin of the A/D channel to which the resistor was wired, an LED on the Front Panel lit up.

Bob Schor