回复： monitoring sun radiation

[Amonds]

I am trying to derive the kWh from the sun's radiation using a Kipp&Zonen CMP11.

I have sampled readings from the CMP 11 (which is in Watt per square meter) using an agillent mux.  Now I have to integrate it over the accumulating time to get the Watt-hour.  Which function can I use?  Can I use the Time-Domain Integration vi SUM[X(dt)]?

[DSPmchen]

You can use Numeric Integration VI.  It locates at Mathematics >> Integration & Differentiation palette.

[Amonds]

Thank you,

I forgot to mention that I am doing real-time sampling and accumulating the kWh continuously.

I tried the Integral (Sum[Xdt]), also in the math palette, and seemed rather straight forward to implement. I have not seen anyone use this vi for this purpose, perhaps its a new feature in Labview?

I am not certain of how to use the Numeric Integr VI for the same purpose.  What do I use for dt (interval size)?  The sampling period?

[DSPmchen]

Which VI do you use? The Integral x(t) VI?

Yes, dt is sampling period.

[Amonds]

 This is what I used.  Its in the math > Integr & Diff > Time-Domain Math

[DSPmchen]

I see. 

You said you are doing real-time sampling and accumulating the kWh continuously.

Do you mean point-by-point?  That is, every time you get a sample data input, you want to calculate the integral?

If so, you can use Integral x(t) PtbyPt.vi, which is in Signal Processing >> Point By Point >> Integral & Differential PtbyPt palette.

[suntest]

How were you able to take measurements with your CMP11? I have a CMP3 and am having difficulty reading the microvoltage created with my compactdaq. would you mind sharing your block diagram?