08-06-2008 10:14 AM
Dear All
I’m using cRIO-9074
NI-9225
NI-9239
LabVIEW 8.5
LabVIEW FPGA 8.5.1
cRIO 2.4.1
I’m Acquiring Voltage signal from Channel 0 in NI-9225 and current from Channel 0 in NI-9239 I have 2 problems.
The First problem is the signal acquiring fine (The voltage signal in index 0 and the current signal in index 1 in DMA) but in a few time the Value in DMA is change between to channels (The current signal in index 0 and the voltage signal in index 1 in DMA) and return back (The voltage signal in index 0 and the current signal in index 1 in DMA).
The second thing is The Cycle Average and RMS .VI Measure RMS for 1 Cycle; I need Measure RMS for half cycle.
How Measure half Cycle?
Please send to me the solution of this issue.
Regards
Spring
08-07-2008 04:13 PM
08-09-2008 12:28 AM
08-11-2008 02:28 PM
Hi Spring,
Your code is huge and I'm missing some of the vi's needed to fully open it. Looking at it, I'm not sure how the signals would get crossed but the only thing I can imagine is that somehow in the indexing for loop something goes wrong as you read the data into the FIFO. You might try using two separate FIFO's, one for each channel. Regarding the RMS measurement, you have to have at least one cycle. If you wire anything less than 1 into the cycles input it defaults to zero and throws an error. This makes sense, as you need at least one full cycle to accurately measure the RMS of a signal.