# LabVIEW

cancel
Showing results for
Did you mean:

Solved!
Go to solution

## Plotting a position using two voltage signals on a graph in LabVIEW

I am a new user with LabVIEW and I have got 4 analog signals from a duo-lateral Position Sensitive detector (PSD) and then i have done math on them and reduce then to two(X and Y co-ordinate). PSD will give the position of the signal in terms of voltages. If the position on the PSD is in the center then X and Y will be zero and as the position of the signal on the signal changes the X and Y voltages change, thus we get new position. Now what I want to do is trace the movent of the signal on the PSD on a graph in LabVIEW simultaneously. I am sampling simultaneously at the speed of 1KHz.

Can anyone help me out with this application ?

Thank You

Message 1 of 12
(3,102 Views)

## Re: Plotting a position using two voltage signals on a graph in LabVIEW

If I understand you correctly, I think an Express XY Graph would work for you as the simplest way.  There are better solutions, but as a new user, I think it would work for you.

-Matt

************ kudos always appreciated, but only when deserved **************************

Message 2 of 12
(3,092 Views)

## Re: Plotting a position using two voltage signals on a graph in LabVIEW

Thank You for the reply, but I am not able to find the Express XY Graph. I am using LabVIEW 8.2, when I search for Express XY graph, it doesnt return anything.

Message 3 of 12
(3,088 Views)

## Re: Plotting a position using two voltage signals on a graph in LabVIEW

OK, try this....

************ kudos always appreciated, but only when deserved **************************

Message 4 of 12
(3,084 Views)

## Re: Plotting a position using two voltage signals on a graph in LabVIEW

Thank You, this seems to be a good start. I start working on this and let you know about some of my other requirements.

Message 5 of 12
(3,079 Views)

## Re: Plotting a position using two voltage signals on a graph in LabVIEW

I have attached the file that I made using the Express XY graph, But I dont think that the plot is of V1 v/s V2. I have also attached a photo of what I am looking to create. Thank you
Message 6 of 12
(3,063 Views)

## Re: Plotting a position using two voltage signals on a graph in LabVIEW

Your express XY graph would work better if you didn't reset the data each time. The input to Build XY Graph that is labeled Reset - wire a False constant to it. Your other xy grpah is completely wrong. You are writing a new cluster array to the graph with each iteration and it's not even the correct type of cluster array.
Message 7 of 12
(3,053 Views)

## Re: Plotting a position using two voltage signals on a graph in LabVIEW

Why dont you use a shift register to build an array of all the past x,y pairs. Then send this array to the xy graph. This will give you a visual display of the xy position in real time:

Or if you just want the location at a specific time :

Message Edited by Cory K on 02-23-2009 02:05 PM
Cory K
Message 8 of 12
(3,052 Views)

## Re: Plotting a position using two voltage signals on a graph in LabVIEW

I had a couple of questions:

1. What has been used as inputs to the shift register for the first solution ?

2. What has been used to join two arrays ?

Message 9 of 12
(3,020 Views)

## Re: Plotting a position using two voltage signals on a graph in LabVIEW

Looks like he has just numeric controls hooked up as the inputs for the shift registers.  Those are fed into Build Array functions, so the data from X and Y will become an array getting longer after each loop execution.  Of course, you would want to replace the numeric controls with your own data acquisition VI's or whatever.

The function that joins the two arrays is a Bundle function.

Hope this helps.

-Matt