LabVIEW
Data Acquisition Rate and .lvm column headers
Your rate input is wired to a constant of 50000, independent of any value in your rate control.
(Sorry, my help is limited because I cannot inspect your assistant configurations (I don't have any drivers installed). Also dynamic data wires are hard to debug because we cannot really tell what they contain. Most users use lower level function to have better control over what's going on)
Hi ramirez,
@ramirez2112 wrote:
Let me just preface this post with a couple of comments:
- I have a VERY limited knowledge base of Labview
- I apologize if this has been discussed in previous forums. I've tried searching for these topics and I think I just need a few tips to help me out of a pickle.
- I was provided this .vi that was developed a long time ago by someone who isn't working with us anymore. And those of us who use this .vi (among other .vi's) have very limited knowledge in Labview. I think we've only scratched the surface of what Labview is capable of.
Well: I recommend to take those "Training resources" offered at the top of the LabVIEW board to actually learn LabVIEW!
Most of your problems come from "having just a limited knowledge of LabVIEW", mostly shown by relying on those ExpressVIs. When you would use "plain" LabVIEW functions instead of ExpressVIs you would get much more control over your program!
@ramirez2112 wrote:
How can I adjust my data acquisition rate to read correctly? I have it set to 100Hz on the main screen, but the data does not come out to 100Hz in the .lvm file. At times, I need to acquire data at slow rates (say 1 data point every 10 seconds). At other times I need to obtain data at high rates (100-200 data points every second). If I put in a lower value, it doesn't seem to track correctly. What should I change to be able to specify if I need 1Hz or 150Hz and be able to output that data?
- Which hardware do you use? Which sample rates does it allow?
- Your VI sets a constant samplerate of 50 kS/s, all you do is requesting a different number of samples!
- When you try to set 100Hz: which samplerate do you actually get?
- Your VI uses two DAQAssistents to read samples, but using very different settings regarding samplerate and acquisition mode: have you done any reading in the LabVIEW help and knowledge base to learn about those settings?
@ramirez2112 wrote:
When I output a .lvm file, the column headers all read UNTITLED. I would like for them to be the same name as the signal that I'm acquiring. Since I have several transducers (torque and force), I need the headers to be able to distinguish the data that's being collected. What should I change in the attached .vi to be able to do so.
Have you tried to set some names for your data channels, even by using more ExpressVIs?
(Again I prefer not to use ExpressVIs to get full control over your VI…)
Btw. saving data directly in a DropBox-controlled folder might result in even more problems…
