Feedback on Getting Started with CompactRIO - Logging Data to Disk

[YongqingYe]

Hi Moris,

First of all, according to your attached screenshot, I'm not sure where you streaming TDMS files, current TDMS supports RT, but not for FPGA.

Secondly, TDMS doesn't support FXP data type now. Maybe we can double check in your code whether this is the reason why TDMS returns error. Would you please let me know which version of LV you are using? Technically, when you wire FXP to TDMS Write "data" terminal, the wire should be broken. 

Thank you!

[Moris]

Hi Yongqing,

I am writing to a TDMS file in RT and I am using the LabView 8.6.

Apparently as you mentioned TDMS does not support FXP. That is fine by me. I can get rid of that error by simply converting the "data" to other type. However, the problem is even when I convert the data coming out of FIFO to other types (Let say DBL, SGL, I16, etc) my data does not make any sense.I guess it has to do with the type of data that I choose for my FPGA FIFO. When I choose I16, I get meaningful data, but I need to work with floating numbers, interger is not enough for me.

When I choose the data type in FPGA FIFO to be FXP, I have this problem!

[waiki.wu]

I did a slight alternation to this exercise and find out the "Number of Elements" in the FIFO read is not actually "wait the number of elements read", it is the actual number of elements gonna read from the FIFO. I have attached the screwn shot here. If there change the "number of elements" in the FIFO read to 250000, it gives me an error, if i change to 0, i got all line of zero, if i change to 6, i got 1 line of data.

[hutl]

Hi,

i am working with a CompactRIO 9074 and a NI 9223 measurement card. I removed the graph from the front panel and added the count to 1, so equal to 1MHz acuisition rate. The measurement shows an overflow after 1-2 seconds. Is there a way to record the data up to 60s? I need the analog data for the measurment of the damage evolution via accustic detection. (At the moment I only record one channel). Do i need an aditional buffer or a queue?

Thanks

[Jacob_K]

I am not sure why you have a For Loop in your code.  It should look something like this.

Seeing as how it only does one aquisition per iteration of the outer loop there is no need to put a for loop inside that is driven by the data from the analog input.

[hutl]

Hi,
thanks, I changed my FPGA the way you recommended, but till now I am not able to reach 1MHz acquisition rate.
I tried some more settings:
I changed the DMA size to 4095 and 8191, but with no result.
Furthermore I tried a higher element number at the FIFO.READ up to 15000 (400-15000) and a Timeout of 5000 (also -1) and adapted the reshape array function to save the same number of elements 15000 (400-15000 highlighted in the pdf).
I also changed the wait function (1-5 ms), but also with out result.
Is it ok to use a waveform graph or is Labview to busy to handle it with 1MHz?

Next thing I think about trying is the “NI CompactRIO Waveform Reference Library” in combination with cRIO Vibration Data Logger Reference Design. But before that I want to figure out what my mistake is.
The goal is a data acquisition of a sensor data (Volt + time) in combination with cRio 9074 and the NI9223. With the final goal of adding two more channels (NI9223 or NI 9215) with a lower acquisition rate (100Hz).

Thanks a lot

[Jacob_K]

Please read the User manual which talks about sampling rates on page: 14

http://www.ni.com/pdf/manuals/374223a.pdf

Here is the KB that talks about how to achieve 1 MS/s

http://digital.ni.com/public.nsf/allkb/5250C3AAE0CBAAE68625777F0072438E?OpenDocument

[hutl]

Thank you very much.

I read both, but still have a little problem. Unfortunatley there was no example file attached in the KB. I did it like in the example and combined it with the realtime part of the data logging. At the moment I get the Error: Invoke Node: Start FIFO in RealTimeCIO. I can not exactly figure out where my mistake is.

I attach my program (1Mhz.pdf FPGA+REALTIME). My NI9223 is in slot 6 (so Mod6) and I only want to get the data from channel 0.

Did I make any major mistake here?

Thank you very much.

[Jacob_K]

In order to better look at your error would you be willing to upload the actual project.  Just zip the project folder and attach it to a post.  That way I can look at all of your property settings.

[hutl]

I managed to get a live stream of the sensor data to a graph. But somehow when I try to record the data by use of a tdsm file I get an overflow after about a second. I attached both programs and the project file. Furthermore I tried it on another computer, just to be sure to avoid any influence of the system.