Voltage vs Current on a XY waveform

[Neil Sampson]

Hi there,

The main problem that I have is plotting Voltage vs Current from an external circuit connected to a Photovoltaic Cell (Solar Panel). Two voltages are measured in the external circuit and are fed into LabVIEW via a LabJack U12 interface card. The current is calculated in LabVIEW by simply dividing the voltage across a 1ohm sense resistor by the resistance. (Ohm's Law)

What I would like to achieve is to plot Voltage vs Current in a graph/chart if I vary the load resistance in the external circuitry connected to the interface card.

I have tried connecting the voltage and current in LabVIEW to a waveform chart via a "Bundle" function and "Cluster to Array" function. An output is produced on the waveform chart
, but not what I require.

Hope someone can help!! Please find my efforts in the attached LabVIEW version 6.1 file.

Thanks very much,

Neil.

[George Lee]

Hi,
Hope the attachment file to be useful. In detail, you can read the example "Variable-time xy chart.vi" in the Labview software.

[Neil Sampson]

Hi George,

Thanks very much for the prompt reply to my query. The file you attached did the job and helped me to progress.

Best Wishes,

Neil Sampson.

[wha@atmel]

Hi Neil,

find attached your .vi with some changes.

I typically use this kind of graph, because it allows
to append some sweeps (in my graph you will find, how
an accumulator was loaded with const. current vs time )
In case you select "single" ,the graph will be cleared.

For your other parameters you only need to copy the
accu vs time stuff.

I think, this gives some more ideas - how it might work.
One additional feature of my graph is - you can print it without wasting black color. How long does it take
until NI has learned how a graph should look like !!! ???

regards
Werner