(configuration of the) hardware slows down my vi ???

[Florian86]

Hello,

yes, sorry i had an enourmos error in reasoning. If I left a DAQmx-Create Channel in the Sub-Vi, the programm speeds up. But only because I have less data or why do you think? And what can I do to speed it up?

[Florian86]

Hello again,

I think my problem could be solved very easy, but I am an absolutely beginner. Sorry if my questions are very stupid.

In my opinion, it could not be, that the measurement of only 4 temperatures and a volume flow slows down the vi. As I said, if I delete a DAQmx-Create Channel in the Sub-Vi, the main-vi gets faster. In the appendix is a picture of my vi. Could anyone tells me where the mistake is?

Thx a lot!

[Suse]

Hi,

don't do the initialize and stop measurement in a while loop because the measurement is stopped and started in every iteration oft the while loop. This slows the VI down.

I'm sure you can delete the while loop around the smaller while loop. Please try this!

Best regards

Suse

[Florian86]

Thx for this hint, but the promlem still exists. Any other suggestions? I am thankfull about any advice.

[Florian86]

Hi,

new try to explain the problem. Now I have simplified the VI (Appendix). Even if I delete the sub-vi ->Sub_Aufbereitung_Daten (I know, then I have weird values) I have the same problem and the program is very slow and can only measure the data with a time-step of 3 sec. The only possibility to speed up the vi is to delete a DAQmx-Create Channel in the sub-vi (Sub_Tasks_Zapfversuch(Appendix2)) But this could not be the solution because I need all temperatures and the volume flow...

[Suse]

Hi,

I suggest you seperate measuring and data logging in two seperate loops.

Initializing the measurement (your sub-VI) and stopping it must be outside the while loop.

If this doesn't work fine, post the modified VI and I will test it on my workstation.

Which hardware do you use?

Best regards

Suse

[Florian86]

Hello,

thx for your help, here is my program.

The Main-VI is H55auptprogramm. The other ones are the sub-vis.

On the frontpanel on the first page, you can set the time-step. Even if you set a time-step of 1000 ms, the programm will update the measured date on page two all 2,9 seconds.

Hardware: NI cDAQ-9174

Temperature NI 9217

volume flow NI 9207 ( I guess)

Thank you!!!

[GerdW]

Hi Florian,

- you're asking for "N channels, N samples", but you haven't configured the "N samples" - you haven't configured timing at all...

- you really should use the cleanup tool from time to time, and especially before attaching VIs to the forum

- comparing complete waveforms for ">0" is kind of silly...

- when you only need the array part of the waveforms, then you should configure the DAQmxRead to deliver arrays...

[Florian86]

Hello,

thx, this are very good hints,

but my problem still exists 😞 but why?

i have only 5 sensors.... The problem isn't t the sub-vi (Sub-aufbereitung_Daten). Even if I delete this sub-vi, the long time-step exists 😞

[altenbach]

How did you implement the hints? Can you show us your updated code?