cRIO 9074 Real Time Application

[Brains]

Dear All

I am working on a real time application with a cRIO 9074 and two NI 9201 C-Series module, in LabView 2014 Professional system.

My task is to create a stand alone application for the cRIO that runs on it without a host PC and logs data. I have already managed to create the application that runs on the cRIO without  a PC, but the data logging does not happen. The aim is that the VI that runs alone will write .csv files to the on board memory. What I do not understand is that, the same program I use in the application is working and even logs the needed data to the .csv files to the cRIO's memory, when I run it on my PC an use the cRIO as a host only. I am using the "Write to spreadsheet file.vi" and a write to .txt vi for a reference, and neither files appear on the memory. I know that the application is running as I am using the USER1 led and an NI TFT Display for visualization and the measured values appear on the screen, if the app would not run the display would not show anything.

My question is that does any of you ever faced this kind of problem, if so can you suggest me a possible solution?

Ps: I use .csv because I am logging the data for a non LabView user, so they can also work with the measurement files with a single MSExcel.

Also I attached 3 pictures about my VI but cannot post the VI itself as it is not my property. The sub VIs contain basic array transformations.

Than You for your answers in advance!

Regards: Brains

[afilipek]

Hi @Brains,

first of all please be aware that your While Loop does not have the Stop condition. It is set to false so it will never stop. Just to try, please make a stop button as a control and then press it to cancel the data logging and see if there is a file with your acquired data. 

If it won't help we will investigate further.

Best,

[Brains]

HI

Thank you for your answer. I have already tried your solution, but it only works if I am  using the cRIO as a host. In real time applications control buttons are not usable as the cRIO cannot handle them. Also I run the loop forever as I am logging data for unknown time duration.

Regards: Brains

[afilipek · Accepted solution]

There must be an issue with either path specification or a write to text file part of your program. I was able to reproduce simple program on NI cRIO-9023(2018 software) and it works perfectly for me on pc and RT level. 

So a bunch of questions:

1) what is inside of the SubVI's before the while loop?

2) how do you specify the path to the controller?

3) why there is a Write function before the loop?

Best,

[Brains]

HI

Thanks for your answer. After your previous comment I was able to make it work. The problam was with the path declaration and a missing loop. Since that everything works just fine.

Thank you again.