07-20-2010 11:00 AM
Hello everyone,
I'm trying to acquire voltage and current data from DAQ devices. My goal is plot current against votlagein a continous plot. As the votlage is increased in 1 Volt intervals every second I want to see how the current is changing. However, these are dynamic data and I need help figuring out how to plot them in a single graph. Any thoughts as to how to plot two different dynamic data against each other in the same graph?
You're help will be very much appreciated.
Thanks
Solved! Go to Solution.
07-20-2010 11:20 AM
You probably want to use the XY graph. The XY graph takes an array of clusters. Each cluster contains two arrays of values.
There are a couple different ways to get there from the dynamic data type: Use the Build XY Graph Express VI, or you can convert the dynamic data and bundle everything up yourself (both methods shown in image below).
Hope this helps!
07-20-2010 01:00 PM
Thank you Alan, that was very useful. However, since I am using dynamic data from a DAQ device, the plot is not continuous. When I have the data acquisition set to on demand I don't see anything on the XY graph. When the setting is set to N samples where I have a given number of samples at a given rate I get small segments of the data. Is there a way to get the data as the voltage is increasing. In other words, when I run the VI, is there a way to how the data is changing in realtime?
07-20-2010 01:31 PM
If I understand what you are saying, it sounds like you want to have the XY graph update with each new data point (or points) acquired, but also want to retain the previous data on the XY graph. If this is what you are after, I'll build on my previous example. For the method of using the Build XY Graph express VI, you can simply double click on it and uncheck "Clear data on each call". For the other method of building the array of clusters, you will need to add a couple shift registers to maintain the array values from previous itterations. Here's the updated image:
07-20-2010 11:02 PM
Thank you again. That is exactly what I needed to know. I'm sorry that my question was not as clear as I had intended for it to be.
07-21-2010 09:03 AM
No problem. Best of luck with your project.
-alan