Labview Data acquisition over days with only logging/recording of data

[Bruce87\]

Ok here goes...

Totally new to LabVIEW. Using the 7 day trail 2017 version. NI cDAQ-9172 with 2 NI9235 connected to windows 10 through USB. The goal is to run 16 strain gauges on a fatigue test and record the data. We figure the amount of data is going to be massive considering we might run for 5+ days so we have decided to only record some of the data. Lets say every 10,000 seconds for .1 second.

I tried in Signal express using the log option but failed to be able to save it to one excel file with a point of reference for time.

Can anyone point me in the right direction here?

[Fred19ni]

hi,

Low level Vi is better for than hight level.

This article can help you save into Excel file Excel save

You can also use tdms file to save your data  save into TDMS File

Best Regards, 

Fred

[crossrulz]

What sample rate are you using?  Strain is typically a slow signal.  So you might be able to cut down your sample rate to make things simpler and reduce the amount of data you are saving.

[wiebe@CARYA]

Well, some obvious advice:

+ Do some courses.

+ Hire an expert (if only to get you started).

+ There are (commercial) LabVIEW products that do this...

And then some:

+ I'd not recommend logging to Excel. Instead consider TDMS (Excel has a plugin) or .cvs (that Excel can read when done right). The "hard" COM binding to Excel in executables is a pain, and updating Excel might break your exe. I've even seen executables fail because Excel was installed with a different language. Not sure if this is still the case in LV17, I've been avoiding it for the past decades after being burnt once or twice.

+ Usually, you want to log when the data is "interesting", so you have a slow log (1Hz) and logs with pre and post triggers around events with fast data.

+ logging slow statistics (1Hz min, max, avg, stddev) might be more valuable then logging fast data at intervals.

+ The logging is usually no problem. Files can be big. The trending is usually the problem. A responsive trend with >100 MB of data is difficult.

And some questions:

+ Is this a test setup or a (internal) product? Totally different situation. The solution could be a quick and dirty if you're the only user, versus a 2 year development to get all the bells and whistles blowing.

+ What is the frequency you're thinking of?

+ Do you have access to hands-on LV expertise (like colleagues)?

+ I'd expect there's a deadline? No time to get 4 years LV experience before you start?

[RTSLVU]

Here is a State Machine tutorial I made for a coworker that basically describes how to do exactly what you want to do.

Record and log data for extended periods, except I am not using any Ni-DAQ devices.  

My example even shows how to automagically create a new data file everyday so you don't end up with one huge file.