Data logging from labview FPGA

[JAHRA]

Hello,

I am working with NI-cRIO 9014 with NI-9104 chassis. I am trying to get analog data from sensor with NI-9219.I am using windows 7 and labview 2017.

I want to acquire data from my sensors so that I have followed a NI tutorial (https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000x3ruCAA&l=fi-FI&nisrc=RSS-crio-en). I have made exactly the same FPGA program for my sensor to get analog data. But the problem is, in the output, I am getting exactly half of the input value. There is no resistor connected. Also in the tdms file , some random values are coming in between the voltage variation (marked in the picture). I don't have much knowledge in LabVIEW FPGA so I am seeking help from experts. Can anyone explain why I am getting exactly half of the supply voltage and why random values are coming?

I am sharing my VI files and image of the TDMS file.

Thank you in advance.

Best Regards,

Nisatuz Jahra.

[crossrulz]

I find it strange you are reading from 4 analog inputs in the FPGA, but you are treating it as a single channel in the RT.  Are you only using 1 sensor (in which case every 4th sample will be real)?  Or are you using 4 sensors (in which case you are interleaving your channel data)?

[JAHRA]

Thank you for your response. Yes, I have made it for 4 channels but I am using one channel for one sensor. I thought It will not affect the overall output. Should I only keep the channel I am using?

Best Regards,

Nisatuz Jahra

[crossrulz]

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@JAHRA wrote:

Yes, I have made it for 4 channels but I am using one channel for one sensor. I thought It will not affect the overall output. Should I only keep the channel I am using?

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Your FPGA can still read 4 channels, but then you need to make sure you are doing something to only extract the data you need on the RT side.  The simple way to handle this would be to use Decimate 1D Array expanded to 4 elements and only keeping the first array.

[JAHRA]

I added Decimate 1D Array but it's not connecting with the index array anymore. Should I place something else instead of the index array?

[crossrulz · Accepted solution]

Get rid of the Reshape Array.

[JAHRA]

Hello,

After getting rid of the reshape array, there is no data coming in the output at all. And now, in the ftp server the tdms file is showing up. Is there any other way?

Thank you for your time.

Best Regards,

Nisatuz Jahra.

[JAHRA]

Hello,

Thank you so much for your help. My program is working now.

Best Regards,

Nisatuz Jahra