LabVIEW

cancel
Showing results for 
Search instead for 
Did you mean: 

Append Waveform, keep time stamp

Solved!
Go to solution

I am reading from a USB module with data acquisition at 500 Hz. In order to achieve this within the loop time, I need to acquire multiple samples per loop. Once I have those samples (output in waveform), is there a way to append the waveform that maintains the time stamps?

 

I am currently using the "get time array", then inserting that data into a shift register of the same. I'd like to re-insert that data into the rest of the appended waveform to make writing the information that much easier. If that doesn't work, I'll probably just stick to making a 2D string array to write the data.

 

Thank you!

0 Kudos
Message 1 of 28
(5,217 Views)

Look for the Append Waveforms VI.  It is in the Waveform->Analog Waveform palette.  I think that does what you are looking for.


GCentral
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines
"Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God" - 2 Corinthians 3:5
Message 2 of 28
(5,206 Views)

I tried the append waveform, but when I do that all dt and timestamp data appears to be removed (dt goes from .002 to 1)

0 Kudos
Message 3 of 28
(5,193 Views)
Please show your code. You are doing something wrong.
0 Kudos
Message 4 of 28
(5,182 Views)

I am using Labview 2014, and have included the .vi and picture.

 

 

Download All
0 Kudos
Message 5 of 28
(5,144 Views)

Here is the picture with timing visible.

Append Waveform

0 Kudos
Message 6 of 28
(5,140 Views)
You have an unitialized shift register. That is why you have the default dt of 1.
0 Kudos
Message 7 of 28
(5,133 Views)

Do I need a seed value for the initialization? A constant doesn't appear to solve the problem. Thank you for your help on this.

 

Appended Waveform example.JPG

 

 

0 Kudos
Message 8 of 28
(5,126 Views)

I'm hoping to be able to be able to keep the t0 data from the first measurement.

0 Kudos
Message 9 of 28
(5,125 Views)

You need the correct dt and t0 in the initalizing constant Leave Y and Attributes empty.  dt and t0 of waveform B are ignored by append waveform and the dt and t0 on the SR will be preserved and propigated through the loop.

Capture.PNG


"Should be" isn't "Is" -Jay
0 Kudos
Message 10 of 28
(5,110 Views)