how to display EEG signal with labview

[Dennis_Knutson]

Well, is the vendor provided application running at the same time? I'm also assuming that you used the Import>Shared Library in order to create the Call Library Function Nodes. Lacking the hardware and the BioGraph application to run, I don't know how much help I or anyone else can be. You need to localize where the error is being generated. I don't think you need to be running all of that code in a constant loop. Start with something simple such as the connect function and make sure the BioGraph app is running when you try this.

The api is a com interface (ActiveX) and does not require that you run the BioGraph app at the same time. This gives you more control but may take more time to implement. You would use the Connectivity>ActiveX functions for the api. First an Automation Open and then appropriate Properties and Methods.

[orchid]

Hi Dennis,

According to your guide, I try to make my vi, but I got some problem..I do not know how to start.Can you give me an example or an idea on that?

Thanks 

Message Edited by orchid on 09-09-2008 11:31 AM

[Kameralina]

Hello,

As Dennis mentioned, you can use the ActiveX VIs.  You will need to use Automation Open and specify the reference for your instrument, and you can use the Property Nodes and Invoke Nodes to call specific properties or methods from your API.  Which part specifically are you looking for help with. 

You can look at LV Help documentation to get more understanding:

Using ActiveX with LabVIEW

ActiveX and LabVIEW

[orchid]

OK, I got it..But now I have a problem regarding the vi. the output did not appear..maybe I have wired a wrong property..but I do not know where and how to fix it. Can you all figure out and give me an idea how to solve it? thanks.

Message Edited by orchid on 09-15-2008 12:07 PM

[Karunya_R]

Hi Orchid,

I looked at your VI and have a few questions. 

• Which Output are you looking? Is it the graph?
• What you using the property node for?

• Can you please post a version that doesn't have as much information on it and try to narrow down the problem to a single point?

Thanks!

[orchid]

Hi Karunya_R,

Yes, I am looking the output from the graph.. Then, I try to see with an array too..

What do you mean by the second question? I am using the property node to acquire the EEG signal from the third party hardware.

Here I attach the problem that I am facing now. Is it possible to use while loop to acquire the signal? Do anyone have a suggestion?

Thanks

[Dennis_Knutson]

Let me butt back in. You are obviously not getting any data back. The number of samples available is 0. That says to me that you are missing something in the configuration of the instrument. Either you need another method/property or you need to change something about the ones you are currently using. See if the vendor has any example code in any language. The property/method names will be the same and perhaps someone can help you translate the code into LabVIEW.

p.s. Your conversion of the scalar to an array is just silly. Even if you got data back, all that you would ever see in your graph is a single point. If you want to plot over time, just wire the scalar to a chart. If you really want to use a graph, then you could use a shift register with a build array function (two inputs - the shift register aray and the new scalar). First though, you need to get data.

[orchid]

Maybe is it true that I have missing something or need to change something, but I do not know to figure it out. I think my problem now is regarding to the notification property. The property have 2 type (put/get). Before this, I am using get function, then when I try to use put function, I still get the sample available value 0. Here I attach the block diagram. Please look at it and give me any idea to solve this problem.

Thanks

[orchid]

Here I attach the Notification property

property [read/write] LONG TTLLive::Notification[LONG liChannelHND]

Description : This property controls the issuing of TTLAPI_WM_ON_CHANNEL_DATA notification messages associated with the specified channel. A positive value enables notification and specifies the number of samples that need to be already buffered before TTLAPI sends a notification messages to the client. A zero value inhibits notification for the specified channel. Parameter : Valid channel handle. Possible property values: nonnegative integer. Default: zero (inactive)