Recording signal

[Nadjil]

Hi,

I am new with LabVIEW. I need it for my project. I am using USB interface board (k8055). I know it is not good to use it, but I have to use.

I don't have counter on this board. I need to record a signal and transferee it to a file where I can look to the time when the pulses is generated.

I have a sensor this sensor send pulses to the USB interface board (k8055). I want to measure the time between each pulses and the duration of each pulse.

I though about a timer. I have found timer on the forum, but I does not work with what I build.

As I mention I am new in LabVIEW. I use LabVIEW 2010

[ThiCop]

Hello nadjil,

Some sentences in your post below are not a 100% clear to me:.

What you you mean with the following sentences:

" I have found timer on the forum, but I does not work with what I build."

" I know it is not good to use it, but I have to use."

Can you share what you have already tried and what went exactly wrong?

PS: Doing a search with google shows me that interacting with that specific velleman board should come down to calling a dll.

[Nadjil]

Hello ThiCop,

I am using interface board from Velleman. I need to record a signal from a light gate. My signal is pulses. I have to measure the time between each pulse. k8055 does not have counter. I want to build counter for that.

I am using waveform chart for that, I though about exporting the data to excel after I finish. But I don't know if this is the best way to do it.

I am new with LabVIEW.

I add my work, I don't get any results. I have to make counter or timer. Adding with my signal to get my data. I don't know if this is the best way to do it.

k8055 use only I32, I need double to use the waveform chart.

Do you have better tips or advice for me to build my project?

I use LabVIEW 2010 on Windows XP.

K8055 does not work on my Mac with LabVIEW 2012

[ThiCop]

Hello Nadjil,

When you claim that you "do not get any results":

Do you then mean that you are not able to read any data from the device or do you mean that your timer doesn't work?

In case 1: Can you provide me with a link to the software installer that contains the dll that you're using (seeing that I don't have that velleman kit at my side)

What have you already done with LabVIEW (or other programming languages) before this project?

Have you ever worked with DLLs?

Did you write this code fully yourself or did you partially get it from somewhere online?

Thanks in advance for your feedback!

[Nadjil]

Hello ThiCop,

I build my sensor, I got signal. But I don't know how to finish the LabVIEW part. The recording of my signal and measuring the time between each pulses.

My signal is coming form the sensor (Light Gate) when the light gate is cut, I got a signal. I want to record this signal.

I need to build a time in msec. And save this signal. After that I need to know the time between each pulse for my signal. I will get about 60 pulses in a min. But I want to get accurate time in msec. this is important for my work and for another research need to be done.

Because I am new will LabVIEW, I don't know which blocks I have to use for my project or how to build it in a correct way.

The program of k8055 I have it, I download it from internet it is for free. Also there are a build blocks function in LabVIEW for k8055. I am using it for my project, I have to build my project part only.

I am not using another programming language, I am using LabVIEW. I found interesting for me, but I don't have the knowledge and the time issue is important for me. Because I am master student and have dead line for my work. 

[ThiCop]

Hello Nadjil,

I think you might have missed my question!

"Can you provide me with a link to the software installer that contains the dll that you're using?"

If you provide me with this link, then I can be sure that I'm using the same software version as you.

This way I can try to help you.

[Nadjil]

Hi,

This is the link where I download the file for K8055

http://www.velleman.eu/support/downloads/?code=K8055 

In the attachment I add the original file of K8055 and the other two file my work. It is working now, I recorded my signal after I build the counter. But the time it is not accurate 100%. Depend on how fast is my computer. I am thinking if there is a way where I can add both file in one file and run it, but I don't know if the counter will work because each counter have a different time. For the triggering part I need sec. for the acquisition_time I need the time in msec.

My teacher don't pay a lot of attention to that, but I would like to know if there is a solution for that? 

Kind regards,

Nadjil 

[ThiCop · Accepted solution]

Hello Nadjil,

Thanks for this extra information!

Below some feedback from my side:

1) In the acquisition VI you now read out data and log to a file (together with some "time information")

    The time you're currently getting is coming from the Tick Count VI and will only give you information about when the DLL was called.
    This can give you indeed information about when the acquisition is done, but it will never be completely accurate.
    You might be able to make it a little bit more accurate by putting both the call to the "ReadAllAnalog" function of the dll and the calling of the Tick Count VI in the same Flat    Sequence Structure. This way you could maybe get a bit more accurate information about when the DLL is being called.

    However, this will still not be exactly the time the actual acquisition is done on the velleman board.

2) When you talk about "the counter" what do you exactly mean?
    Are you talking about the data produced by the tick count VI?
    Basically the information you can get from this is the relative time difference between different calls of the "ReadAllAnalog" function of the dll.
    Just subtract the first "tick count" from all the proceeding ones.

3) It is still not clear to me why you need to reopen the connection to your device in each iteration of your for-loop.

4) It is also not clear to me why you put your wait until next ms multiple VI in a for-loop with iteration 1?

    The reason for the addition in that for-loop is also unclear for me. It is not being used anywhere, so it can be removed.

[Nadjil]

Hallo ThiCop,

I worked on my project. I did changes in both file.

Accusation time, is get better after all, better than before. I have more accurate time. I know K8055 is not good. I am also using virtual machine on my MacBook Pro this not good. I hope next test I will be working with Windows.

Note: My English not so good.

I add the both file I used for my work after I improved it, thanks for your help.

[ThiCop]

Hello Nadjil,

A lot of people here have English only as their second or third language (my case), so that's not a problem at all.

I don't know what your native language is, but it can be useful to know that we also have NI Discussion Fora in other languages (eg. French, Portuguese, Spanish, Italian, ....) if you feel more comfortable in those languages.

You can find them at the bottom part of the forum-page https://forums.ni.com/