NI 6009 DAQmx data adquire

[johnsold]

The sample rate and the number of samples together determine how much time will elapse while you are taking the samples. You have the VI set to sample at 1000 samples per second or one sample every millisecond.  20 samples will occur in 20 ms = 0.02 s.  Your time constant is such that it takes about 0.6 s to fully charge the capacitor. So you need to collect about 600 ms of samples WHILE the charging is occurring. You have no means of triggering the data acquisition when the button on your circuit board is pressed, so you need to start sampling before you press the button and collect an unknown number of samples for an unknown amount of time to be sure to capture the effect.

It is not clear what you really want, so we cannot tell you how to do it other than in general terms as above.

Lynn

[jocuma]

mm thanks, I really want to take the voltage during 5s

second 0 -> voltage

second 0.2 -> Voltage

second 0.4 -> voltage

second 0.6 -> voltage

second 0.8

second 1

second 1.2

second 1.4

second 1.6

....

In every second I want the voltage...it's like now but with less samples and I don't want the 00 00 00 00 01 01 01 01 01... I'm very frustrated aboout this ...bff

Maybe in the table...it's necessary a counter or I don't know ...but I want what I said here of this example ... S:

[johnsold]

Overlapping posts.

Suppose you collect data at 1000 samples per second for 5 seconds. During that 5 seconds you press the button for about 1 second and then release it. Now you will have data the looks very much like your image.

If you only want the segment from 2.1 s to 2.7 s, you can use Array Subset or Get Waveform Subset.vi. If you want fewer points in that subset, you can use Decimate Array, or Index Array and Quotient & Remainder.  Read the help files for those functions and VIs to get more informationabout how to use them.

Lynn

[jocuma]

you want to say something like this?

http://forums.ni.com/t5/LabVIEW/get-waveform-subset-not-able-to-get-desired-result/td-p/1089259

thanks for the help 🙂

[jocuma]

But...somthing that I said like this

mm thanks, I really want to take the voltage during 5s

second 0 -> voltage

second 0.2 -> Voltage

second 0.4 -> voltage

second 0.6 -> voltage

second 0.8

second 1

second 1.2

second 1.4

second 1.6

....

is it possible to do? :S

[johnsold]

Take the tutorials as suggested by others. Read the help files. 

Lynn

[jocuma]

I don't think that it's a good solution because It only works reading 5000 samples and I only want 20....

[johnsold]

Change the sample rate.

Lynn

[jocuma]

I changed a lot of times and the problem continiue...

bfff I don't know what I hve to do ..

[johnsold]

The sample rate is the 1000 constant you have wired to the rate terminal of the DAQmx Timing.vi. That tells the 6009 to take 1000 samples per second.

Lynn