ECG Signal analysis

[RavensFan]

Please attach your image to your message and not to a third party website.  If that website changes in the future, the link to it will be broken and the image won't show up in your message.

The problem is you are trying to read the file at the same time your are writing to the file.  It is likely that on the first iteration, the file will get read before the data is collected and written to it, thus an empty file.  You need to break the read from file completely out of the loop.  I'm not sure you truly need it at allas the dat should still be present on the other waveform charts as long as you haven't exceeded their history length.

[Tomo8281]

Well i still want the read/write function so you can see previous/different ECG signals, part of the program im making and i didnt really want to put it in a different VI if you can understand.

So ive moved the READ outside of the loop, which makes more logical sense to me anyway. Should the write be outside the loop or not? I don't really know how it works though to be honest. When i send a TRUE to te enable pin does it take a snapshot of the data or does it record for a certain timeframe? I'm guessing it records so im guessing it should in INSIDE the loop to get the constant data?

Im trying this, but all i get saved is a lot of 0's in one collum? If i move it outside of the loop, the OK button doesnt work and it doesnt pop up a box asking where to save a file, or do anything at all!

Thanks,

Tom

Message Edited by Tomo8281 on 01-12-2009 01:24 PM

[RavensFan]

You do want the write measurement file inside the loop so all data that is collected gets written out.

If you're not sure about how things behave inside a loop vs. outside a loop I would recommend looking at the online LabVIEW tutorials:
LabVIEW Introduction Course - Three Hours
LabVIEW Introduction Course - Six Hours

[Tomo8281]

Im having A LOT of trouble with peak detection. Im using the peak threshhold detector, but having a lot of problems.  Its the converting it to array i think, just got myself confused! (see attached image).

Also as i cant afford the massive signal toolbox so i cant get my hands on WA Multiscale Peak Detection VI (thats in the link you sent me) im having trouble with extracting portions of signals to get the different intervals :(! Trying to think of a way to notify the 'Extract Portion of Signal.vi' to begin sampling! Then to end sampling.. since i need to capture the wave.

Any ideas? Any help?

Thanks,

Tom

Message Edited by Tomo8281 on 01-13-2009 11:41 AM

Message Edited by Tomo8281 on 01-13-2009 11:42 AM

[Tomo8281]

Anyone have any ideas about the array-peak detection? Uploaded my vi + jpg in the previous post :\!

Just need to sort out how to get all the specific intervals, and as i said i cant use the signal toolbox thing as its too expensive and i only have the base copy of labview!

Thanks,

Tom

[Coq_Rouge]

I guess you have full development system. Since you are using the "threshold peak detector vi". Use help/example finder  and search for "peak detector"

[Tomo8281]

Really? Hmm i swear i dont have that. I did install some packages though!

Also i dont have any of the examples on my pc, ive checked!

[Coq_Rouge]

Strange, are you sure? Look at the picture I have sendt you. Can you find the marked function?

[Tomo8281]

Also another thing. All the examples i have found, have been to deal with arrays. My data is a real time ECG signal that is randomly being generated.

Also are my loops right? Does everything have to be in the FOR loop? :(!

Just need to get detection of the ECG - P R Q S T peaks and ill be able to shoot off and do it all, im just stuck :(!

[freemason]

here is a little peaks and valleys detector, block diagram looks a  little bit messy at this time , but i think you'll understand easily

u can change the cursor style to * or + and use property nodes to place them on peaks/valley (P,Q,R,S,T) as and when they are detected and use those values in your program

cursor is the threshold limit

hope u get some idea from this