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NI-9225 and NI-9227 Powermeter

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Hello guys,


I'm new to labview so i'm still not verty familiarized with all the functions of the software. Right now i'm having troubles measuring Voltage and Current in a Crio-9074.


I have the 9225 and 9227 modules, i know they are for measuring voltage and current respectively but i just cant find a way to interpret the measurement, i tried connecting them directly to a waveform chart (since they throw out a double type output) but it stays in 0, i already measured the voltage of the inputs with a multimeter and there is voltage on the terminals.


I'm actually programming in Scan Mode, i dont know if this has to be done on FPGA Mode, i havent been able to find examples regarding my problem.


Thank you.



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Message 1 of 6
Accepted by topic author joseguzb

the scan engine default is at 10ms (~2 data per cycle for 50/60Hz), you probably want to reduce it to get a better sample of the waveform. 


can consider using a producer-consumer, timed loop as producer, read from 9225/7 to enqueue, queue element being 1D array of double, dequeue in consumer with circular buffer array (fixed size) for further processings (rms, etc).

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Message 2 of 6

Thank you CY, now i was able to reed the voltage values coming from the 9225, the problem is that i have readings of 160v, while i only have 120V AC connected. I already tried with a DC source and it measures the voltage correctly, do you know any particular reason why i might have faulty readings for the AC. i already checked the voltaje on the terminals of the module and there are indeed 120v. 



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Message 3 of 6

Try to check if you are measuring peak or rms, for the amplitude?


Also check if the sampling rate is sufficient.

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Message 4 of 6

Yes i totally forgot about RMS, now im getting the desired value, i just have to work with it, thank you very much.

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Message 5 of 6

Glad you got it working, have a great day ahead

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