topic Re: DAQ Assistant only saves every 2 seconds in LabVIEW

DAQ Assistant only saves every 2 seconds

johng1996 — Tue, 29 Oct 2019 00:10:15 GMT

Hello,

I am very new to LabVIEW and everything related. UrgetnPlease Help.

I need to read and save loadcell values continuously until the code is stopped. I have written a code that reads the loadcell and plots it in a voltage vs time graph. My code only reads them for 0 to 1.98s and goes back to 0 (check the excel screenshot). I want the sheet to have values from 0s to x second (x being the time at which the code is stopped). For example, if the code runs for 2minutes, I want the excel sheet to have time values from 0 to 2 minutes. I am not sure how long it will be running because this code is written for a tensile testing machine I should be reading the values until the stop button is pressed.

Please refer to the excel data and vi code below.

thank you.

Re: DAQ Assistant only saves every 2 seconds

RavensFan — Tue, 29 Oct 2019 00:26:02 GMT

Why are you appending the newly captured waveform with an empty waveform with a dt of .3?

Why are you using Express VI's? I recommend using regular DAQmx functions and regular Write to Text File functions.

Re: DAQ Assistant only saves every 2 seconds

johng1996 — Tue, 29 Oct 2019 00:45:36 GMT

This is the code I meant to share. Sorry about that, it runs every 0.09s.

I am using the VI express because after googling that's what people were using.

Re: DAQ Assistant only saves every 2 seconds

RavensFan — Tue, 29 Oct 2019 02:53:55 GMT

Actually, if you googled more, you'd see the recommendations are to NOT use Express VI's.

But your Express VI is set up to rename the existing file if it already exists. You should pick Append to File.

But as I said before, get rid of the Express VI's and use real LabVIEW functions.

Re: DAQ Assistant only saves every 2 seconds

johng1996 — Tue, 29 Oct 2019 19:53:36 GMT

Got it, I will do more research on how to use the DAQmx and see how it goes. Thank you

Re: DAQ Assistant only saves every 2 seconds

cbutcher — Thu, 19 Dec 2024 21:56:19 GMT

This link (Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications) is a good starting point.