how to search values in arrays

[watha2]

Hello, I'm a beginner in labview, so please help me with my problem,

I got two output, voltage and current,

I also need power, so i multiple the voltage and the current. Then I find the maksimum power using the compare technique, but the problem is, I also need to find the voltage and the current when the power is max, called Vmp and Imp, here I attach the curve.

Thanks for helping.

[johnsold]

If you have the current and voltage in arrays, then the power will be in an array also. Use the Array Max & Min function.  It will give you the maximum value fo the power array and also the index in the array where it occurs Wire that index to two Index Array functions to get the values of voltage and current at that index.

Lynn

[Jyots]

Hi Watha,
If I've got you right, you got 2 arrays. One for Voltage, one for Current. You have multiplied these and got a new array Power. With array max min function, you got the max Power. Now with this same function, you can get the index(if you are using Labview 2010 or above). With this index, using index array function get the values from Voltage & Current arrays. That solves your problem. If you are using lower versions of labview, then you need to use a search 1D array function and find the index of the max Power. Hope this solves your problem.

[watha2]

Yes, you got that right.

But, how to use index array?

I tried to wire the array from power to the input of index array function. But I don't know what to do with the index, which index i need to input so I can acquire Vmp and Imp?

[Nghtcrwlr · Accepted solution]

You need to connect the index from Min Max function to index array function to get the max.

See attchemnt below

[GerdW]

Hi watha,

the ArrayMinMax function has 4 outputs. Read the context help to decide which output would be useful in your case...

[pjr1121]

Looks like your trying to analyze I-V curves.  Here is a sub-vi I use for this purpose.  Note, that my subvi is build to use current density (mA/cm^2) as the units for the y-axis.  Change VI accordingly.  This will output Voc, Jsc, VMax, JMax, Efficiency, Fill Factor, and estimates for series and shunt resistance.

For the resistance estimations, the sub-vi assumes a certiain number of data points beyond Jsc and Voc (to attain a linear fit at those points)

[watha2]

Thank you very much for helping me.

I'be just lost my netbook so I forgot to accept your solution.

Thank you again.