Create a Force vs. Time Graph Using an Accelerometer and Known Mass

[jharman7]

So I have a VI created that will take the voltage given by the accelerometer and translate that to the acceleration from an impact. I'm very new to this and am now having great difficulty trying to add to this program to create a Force vs. Time graph, as well as extracting max / min values in the force graph. Any help would be much appreciated, I've attached the current VI to this. Also, if it helps I'm only using LabView 8.6.1

[RavensFan]

One problem I see.  You are collecting 10,000 samples at 1000 Hz rate.  That means 10 seconds worth of data.

Your timeout value is also 10 seconds.

You'll get a timeout error right about the same time you are finishing your data capture.  Try an 11 second timeout.

[jharman7]

Ok thank you for pointing that out, I was thinking that setting the timeout at when the sample count completes would work, but I'll change that. 

[Bob_Schor]

Here are some suggestions:

• It is curious that you are (a) "very new to this" (which I assumes means "to LabVIEW") and (b) you are working with a 10-year-old version of LabVIEW.  If you are a student, then your University/college/high school should be able to get access to a more recent version of LabVIEW, or you could go directly to the NI Site and download an Evaluation or a Student version of LabVIEW 2018.
• It is not clear (yet) what you want to do.  You have an Accelerometer (how many axes?) and are using it to record an "impact".  Can you say anything more about the parameters of the study?  Over what time interval will the measurement be made?  What time resolution will you need?  How will you synchronize data acquisition and whatever it is that initiates the impact, i.e. are there other hardware interactions involved?
• I notice that you are almost exclusively using Express VIs (including my Least Favorite, the Dreaded DAQ Assistant) and the equally obscuring Dynamic Data Wire.  You would have (I believe) a much easier time planning and implementing your Design if you learned some basic LabVIEW (Loops, Case Statements, basic LabVIEW Data Structures such as Arrays, Clusters, and Waveforms), and learned a little about DAQmx, the LabVIEW routines that implement Data Acquisition and Control (DAQ).  There are Tutorials on DAQmx on NI's Site, including my favorite, "Learn 10 Functions in NI-DAQmx and Handle 80% of Your Data Acquisition Applications" which can be found (use Google) as both a White Paper and a WebCast/Video.

Bob Schor

[jharman7]

I'm currently doing an unfunded Masters of Science in Engineering, studying the effects of impact loading on carbon fibre polymer sheets placed in pure tension. There hasn't been much dynamic testing done at my university in structural engineering, which is why I assume we only have a 10 year old version of LabView, and as the degree is unfunded, don't have access to a newer version. We have been using strain gauges to measure the strain due to the impact load, and converted that to a force, however the results don't make a whole lot of sense (reading between 6-12kN when expecting around 60kN). This is why I now want to use an accelerometer, attached directly to the drop mass which delivers the load. It's a unidirectional, piezometric accelerometer. I had not expected to need to learn how to program for this, until our strain gauges were giving us odd results, and that is why I'm new to it. I had only began looking into working with this software, in this capacity, the day prior to posting the question on here. I had seen a video online using the DAQ Assistant and was unaware it wasn't really preferable, going off your statement there, and was unaware there were other means of acquiring the data from the accelerometer.