Automation of Acquisition

[jand]

I am using LabView 7.0 Express.  I have a program that measures resulting current from voltage applied and then graphs it on an XY graph.  I would like to make this an automated process.  The problem is that I have to adjust the pointer slider everytime I want to increase the X values on a new measurement.  I would like to have a minimum and maximum for the data range, along with a step increment to be automatically added to X values.  Advice?

[mikeporter]

Right click on the X-Axis and in the resulting menu select "Autoscale X".

Mike...

[jand]

I think you misunderstood my question.  I would like the program to automatically increase the X value, or smu1 value in this case, by a certain increment each time before it uses it for a measurement.  Is there a way to do this?

[Dennis_Knutson]

You don't get very far in this forum by giving someone one star when a question is misunderstood.

Your problem is simple. You wire the start voltag to a shift register, add the increment value to it, and stop the loop when the shift register result is equal or greater than the stop point. There are a lot of other ways this can be done. There is also the ramp function. Check out http://www.ni.com/academic/lv_training/how_learn_lv.htm for some basic LabVIEW tutorials.

Message Edited by Dennis Knutson on 07-16-2007 04:40 PM

[mikeporter]

Move the control outside the loop to initialize the shift register. Next, use the value that is in the shift register as your X axis and add code to decrement the value each time the loop iterates.

Mike...

[aminuteq]

Dennis,

I am having a similar problem as "jand."  I notice that in your while loop there is a box that says "set voltage."  Could you show what that is and what it does?  Also, how can one make it so that the while loop does not repeat until the entire program has completed once?

Thanks.

[Dennis_Knutson]

The subVI is just a dummy one I created. It would be replaced with whatever function you use to actually set a voltage (or whatever). I put it there so that it would clear that the setting of the voltage should be done before the increment.

I don't understand your last comment. A while loop always iterates at least once and all of the code that is inside the while loop will be executed before it wold iterate again.