read form file and send to PCI

[wasabi22]

hi everyone, i'm a student and a neophyte of labview and i use 8.6 version.
i need indications for a project. I should read sampled data (saved in txt file like 200_1.txt) from ECG signals and send it away to a PCI6733 to generate analog outputs to reconstruct the ECG signal and then go to test the electrocardiographs.

I've found GenerateFromFileLV86.vi to read data from file. Is it ok for my project? i don't understand how to set daqmx to send data to PCI and how i should display data (like oscilloscope)? 

Finally have you some examples that help me?

P.S. sorry for my bad english i hope you understand me!:-)

[H_SH]

Hey wasabi22,

This should be easy to do using the DAQmx VIs .. U just need to download the VI from NI (http://decibel.ni.com/content/docs/DOC-7336) then little change in seperating time stamp with voltage values.. In your voltage file u have three rows instead of two in VI downloaded. so seprate the file in three different array one for time stamp and two other for voltage values in rows.. for that you just need to pull down index array one more time and take subarray output.. now you have three array for play so file reading and seperation is done ...

Then based on your requirement if u want to show any one voltage row on selected PCI output channel then select according voltage array to put in input of write VI..

Incase of showing both at a time, u need to create one more analog voltage channel and follow the same steps as in the link above..

be aware of note in the link "This example is not meant for deterministic signal generation. You will notice that each iteration of the loop will take about 1-2ms longer than the calculated time delay."

hope that helps

HS

[wasabi22]

Hello HS, 

I changed my VI to read and display up to 8 columns of tension (attached generatemodificato.vi)

I don't understand how I should view the waveform that send to analog outputs (like oscilloscope)?could you give me some examples for this?

I have a terminal SCB-68 Should i take the signal from there and connect it to the oscilloscope or 

it can be done via software?

I don't understand what mean the message: "This example is not meant for deterministic signal generation. You will notice that each iteration of the loop will take about 1-2ms longer than the calculated time delay."

sorry but i'm a principiant

[Dennis_Knutson]

Don't make modifications when you have no idea what you are doing. Take the LabVIEW tutorials and Getting Started with DAQmx.

Your indexing of colmn 8 is silly since your text file has only 3 columns. The VI already has graphs that display columns 1 and 2 so your question about an example/software for it does not make any sense since it is right in front of you. If you want to look at it with a scope, then just connect it to the output.

The message would be clearer if you had gone through the tutorials. The example writes one point at a time. What I would do is use the dt calculated inside the loop and create a waveform data type with that. You would then pass the entire waveform to the DAQmx Write after changing it to N Samples. A for loop would not be used. Go to Help>Find Examples>Hardware Input and Output>etc. and find dozens of examples.

[Dennis_Knutson]

Something like this.

Message Edited by Dennis Knutson on 05-31-2010 10:25 AM

[H_SH · Accepted solution]

Hey wasabi22,

I completely agree with Dennis and suggest you to go through tutorial as ur unknown experiment may result in hardware failure .. for time being i can just suggest you two step at VI level, shown in pic below and please go through connection chart of SCB-68..

this link (http://digital.ni.com/public.nsf/allkb/F011AD8B0F4BD35086257050006CBB70) should help you with SCB-68..

The three step you need to perform:

1) drag down the array index tool as shown in pic but just one time .. your three row will be seperate now.. from time being i m just considering to show your one voltage channel row just after time channel.. so after dragging just leave the things unchanged here..

2) move to front panel and browse the PCI channel for output..

3) read the SCB-68 connection from link above and wire it to oscilloscope w.r.t PCI channel u selected..

Then run the VI to see the result on oscilloscope.. If you have any confusion first clear it then play with hardware stuff..

Hope it helps

HS