Creating a IV Graph while using a NIDAQ850

[nistule]

Greetings,

So I am new to labview and have need to create a little program over the weekend that will do the following:

Output a voltage and measure a current. The voltage should be able to have a max and min set, voltage start value, number of cycles and a scan rate (voltage charge per sec)As well as that I would like the program to store to a file the Time value and the voltage in a simple file. 

Now currently my major issue is getting the voltage to output to the IV graph at all. I've also had problems getting the graph and the DAQ to do what I want.  ANY Help here would be GREATLY appreciated.  Bellow is a link of what I have right now but I think it is probably not quite what I want... I have also seen some mention of having to get the two graph inputs to sync up and I'm not quite sure how to go about that just yet.  Please help!

I am using labview 8 and a NIDAQ850

[RavensFan]

You will probably want to add a loop structure, and also build up some arrays that are fed into shift registers.  Your code will run one time and generate a single X and a single Y value.  These will feed into the XY graph as a point.

I would recommend not using the Build XY graph Express VI.    But if you do use it, uncheck the box that is clear data on each call.

I have a question for others out there.  I was doing some experimentation with this VI to see how that express VI worked.  There is an X input and Y input in.  But when I put a probe on the cluster coming out, it showed 2 arrays, both of which were labelled Y.  Why?  The upper one did consist fo the X data.  See below.

Message Edited by Ravens Fan on 06-10-2007 09:55 PM

[RavensFan]

Okay, I found out why.

Within the Express VI is  a subBuildXYGraph.vi the X data gets fed into a Get Waveform Component VI.  It's output is designated Y.  The Y data gets fed into the same VI and is also designated Y.  So the output of this subVI is two arrays that are labelled Y.

Could you call this a bug?  The code works, but it is a nuisance and can confuse new users who would be the most likely ones to use an Express VI.

Message Edited by Ravens Fan on 06-10-2007 10:05 PM

[SamboNI]

Hi Ravens Fan,

Thanks for isolating where exactly this occurs. While I wouldn't necessarily call this a bug, I would say that this is something that could easily be made more clear in the XY Graph Express VI. Clusters can have two elements with the same name, which can get confusing when unbundling or probing.

I have filed a Corrective Action Request (CAR) for this matter, ID 4AAF81XX

Best regards,