LabVIEW
Writing Waveform data into CSV file
Hi there,
I have a LV program which contains voltage, current and power data into the same waveform. I am planning to extract each of them one by one and putting into array. Currently, I have extracted only the voltage waveform and converted the data into a CSV file.
However, the problem is that the time stamp (dt) and the y value are in the same cell of the CSV file which requires to post process in excel to get tab delimited format. I would like to get the end result without post processing.
Can anyone help me to correct the code with delimitor?
Moreover, If I want to add two more data (Current and power), how can I append them into another two columns in the CSV file and synchronize with the relative time (dt)?
Hi hk,
@Hk637 wrote:
Moreover, If I want to add two more data (Current and power), how can I append them into another two columns in the CSV file and synchronize with the relative time (dt)?
You just need to add more columns to your array...
To find the correct delimiter you could create a CSV file with Excel and read it in a text editor to actually see the used delimiter char. Usually you could use a Tab, comma or semicolon: Excel can handle them all...
On your VI: replace the local variable by a wire!
What's the point of wiring a constant to the case structure selector?
In assumption that your "Value" array contains all three waveforms and you have the same dt and t0 for all of them, then try this way:
Side notes:
* "Default" Delimeter for Excel *.csv files is ";"
* Avoid race condition between terminal and local variable (you can't say what will be first — write to terminal or read from variable), so you don't need to wire N terminal if you need to iterate over all input array elemenths:
These two construction semantically equivalent:
* And you don't need parallel for loop in this case
Hope it helps.
Hi Andrey,
Thanks for the details code and explanation. I modified the code a bit using event structure and from there I am giving the file path.
It worked :).
Moreover, I noticed that the power data are not correct (P=VI), when voltage is zero. There is still power which is not true I think. Do you think that the time is not properly synchronized?
Thanks in advance.
This is still convoluted and probably wrong. You assume that all waveforms have the same dt (since you only do one time column!), but yet you calculate the same time array N times while only keeping the last one..
See if this can give you some ideas
Hello, I am new to Labview. I am reading 3 phase current data with 3 channels on the oscilloscope. I want to view and save this in Labew. I used 3 channels in Labview and I want to see and save the 3 phase current data coming from 3 channels of the oscilloscope separately from these 3 channels. For this, I connected these 3 channels to the channels input of read waveform.vi. I can see this on the screen with waveform graph. But I want to record these three signals simultaneously as time, u1, v1 and w1 continuously and uninterruptedly to csv.The waveform output of Read waveform.vi is a cluster of 3 elements. I want to decompose this as 3 separate waveforms and then save it with Write Delimited Spreadsheet. Here I can display 3 signals with waveform Graph. However, I cannot decompose these 3 signals. I tried this only for single phase using read waveform single.vi. When I use Unbundle by name, it gives all outputs as sampling period. When I use Unbundle, it gives 2 outputs as sampling period and the other 1 output as array, but the array is mixed and does not belong to the signal. When I use Get Waveform components, it gives an error because the waveform types are not the same. I need to receive these 3 signals simultaneously, separate them and record them for a while.
Can you help me please? I have very short time.
Hi suleb,
@suleb wrote:
I cannot separate the 3 element cluster coming out of read waveform.vi from here. I need to receive these 3 signals simultaneously, separate them and record them for a while. Can you help me please?
You don't tell which scope you use.
You only attach a scaled blurry image.
How should we help with that information?
What kind of "cluster" do you get?
Why can't you use Unbundle(ByName)?
I don't see any FileWrite functions in your code…
@suleb wrote:
I have very short time.
We cannot solve this problem for you…
