How to save measured analog data on the PC?

[Rodzynek]

Hello,

I am a beginner in the real time hardware. I have the cRIO-9024 controller and cRIO-9112 chassis. I have some questions:

1) I cannot see the examples because Labview 2009 shows that The NI Service locator is not running. I have just installed Labview 2009. How I can solve it?

2) How is the best way to filter measured analogue data? There is hardware filtering module or I have to use Labview tools such as point to pint filters? I would like to read data in time step 1 mS.

3)  How I can save measured analogue data on the PC? I have tried to use "write to measured file" but it made my program slower and I could not get my 1 mS of one cycle. Can I use somehow memory of cRIO-9024 and after when the program will be finishing to save files on the hard drive? Maybe it would be faster?

Thank you for any help and examples if it would be possible.

[ninlmartijn]

Dear Rodzynek,

thank you so much for your post on our webforum. For your first question I can reccomend to have a look at the following KB.

You are able to find a point to point filter under signal processing => point by point on your functions palette. You can implement this filter in your realtime VI. It is also possible to implement this kind of filteringon FPGA if you are using FPGA programming on the compact RIO. The advantage is that you offload the cRIO controller (the controller receives only the data you want). In this case you are reading the data in with an IO node then you filter it and transfer the data to the controller using a DMA FIFO.

On a compact RIO controller you are using two loops; a high priority loop to communicate with your hardware IO (FPGA) and a low priority loop for file IO and TCP communication (TCP functions or shared variables). You are able to log the data on the cRIO controller and use TCP functions to transfer the file to your windows envirorment. You can also use shared variables to transfer your measurements, mostly I'm (big fan) using the STM library for data transfer to a Windows UI. You can download this library; templates and examples are included with this library.

Please let me know which choices you want to make (filter on FPGA, data streaming or file transfer), and we can have look to make a more specific example (please send me also the cRIO modules you are using). You are already (if the service locater works) to find cRIO examples under the browse tab => hardware in and output, compact RIO. You can find filters under Analysis and control and DMA FIFO under DMA.

Best regards,

[Rodzynek]

Dear Martijn,

Thank you for response.

1) For first question I found another solution. I went to (in my case) C😕Program Files\National Instruments\LabVIEW 2009\resource\system and there is HelpServer.vi. I started application and start the server and open the port. After that everything is working fine. Now I can work with examples.

2) For filtering I used as you said point-by-point filter. See attachments. My question is if I did it correctly and if it is the best way to do it.

3) I have not tried yet. 

My hardware NI 9265, 9203, 9217, 9263, 9215, 9472, 9481. I have 02 sensor, pressure sensor, flow meter sensor, RTD thermocouple, linear motor, solenoid valve. You can see in the attachment that for example for O2 sensor I have quite much noises  

[jkurtw]

Hi Rodzynek,

Since you are new to LabVIEW Real-Time and CompactRIO, I would suggest reading through the CompactRIO Developer's Guide.

It walks through many topics with recommended architectures for each.

Kurt 

[Rodzynek]

I was trying to do something like in the attachment with two loops with different priorities. But any file was recorded on the hard drive. Where I do mistakes?

[ninlmartijn · Accepted solution]

Hello Rodzynek,

If you don't have the FPGA module (or just for now) the solution you gave with the filter would be OK. Placing a second loop for file IO (and possible your communication to the Windows UI) would be a great idea. Please remember that the file path you are using on the create file function refers to the drive from the cRIO controller (which is mostly a c drive). You can FTP to the RIO controller (using the IP address) and have a look at the files.

One suggestion to get this file programattically is that the cRIO controller sends the file name to the Windows UI (after closing the file), with the Windows UI you can use the FTP functions within Labview to get the measurement file.

Best regards,

[jkurtw]

Hi Rodzynek,

As ninlmartijn said, the file you are creating is on your cRIO controller's hard drive.

An easy way to FTP it off if to use Windows Explorer.

Just open a "My Computer" window and type ftp://<your cRIO IP address>/  and you will be able to browse the cRIO hard drive and drag and drop files to your computer.

Kurt 

[Rodzynek]

Thank, now everything is working correctly. Just if it would be possible post any example with FPGA filtering. It will be very helpful.

[ninlmartijn]

Dear Rodzynek,

great to hear everything works. The past few days I wasn't in the office, I hope to create a FPGA example as soona as possible.

Best regards,

[Rodzynek]

Well, I wanted to go one step further and I have problem with saving files. I wanted to save data, let say, every 10 seconds but in differents files. I did something like in attachment but I see only one file on the cRIO hard drive. I checked this idea without cRIO and it is working. On my PC hard drive the files are saved. Where can be problem?