Available Storage Space, RIO Evaluation 9636 board

[gerin99]

All,

I have recently decided to remove the daugterboard from my RIO Evaluation KIT and will exploit the full capability of the 9636 board attached.  With that being said I am going to use it as a stand-alone board (embedded).  Therefore, what is the max memory available to me on this board (between code space and stored data).  The reason I ask is because I would like to store measured data points over the span of run time and I want to make sure that I never store too much to slow the system down.  For example, if I am storing 10 analog data points every 5 minutes, how long can I safely store data before I should start writing over my own stored data?

Also, is there a specific way to do this with LabVIEW 2013 and the 9636 board?  Will the embedded system allow me to store data to memory?  Do I just save it as an array or do I have to be specific as to where to write it?  Will I lose the data on a power cycle?

Thank you,

gerin99

[Craig_]

Hey Gerin99,

Based on the specifications document found on the 9636's product page here: https://www.ni.com/en-us/support/model.sbrio-9636.html

The PDF notes that the 9636 has 512 MB of internal flash memory (non-volatile) and 256 MB of RAM (volatile).

If we were to compare this system to your computer the internal flash would be similar to your hard drive, and its RAM would be equivalent to the computer's RAM (though smaller in size). For a complete discussion on the differences in volatile and non-volatile memory see these wikipedia pages: http://en.wikipedia.org/wiki/Volatile_memory http://en.wikipedia.org/wiki/Non-volatile_memory

If you want to save data in a way that you do not lose information on a power failure you will need to write it to files on the internal flash. This is done in exactly the same manner as you would write files to your local system, except that the VI doing it would be listed under the target in your project.

To estimate how much space your data will take up on disk you can calculate how many bytes are needed per the precision of the data and knowing how often you are saving find the disk transfer rate.

Hopefully this gets you started on the right path!

[gerin99]

Craig,

Thank you for your response.  That makes a lot of sense to me.  However, the problem I am having is figuring out how to get that data to store on the 512 mb of storage space.  I created a VI that saves the bit data I want and I got it to store in a small size (take less space), howeve, when I perform a shutdown and then restart and try to pull the data it does not find anything.  Could you send me an example or point me to a NI tutorial that shows how to save this data using the read/write commands?  Also, how do I determine how much space my executable is taking up?  This will also limit the amount of saving space I have right?

Thank you,

gerin99

[Craig_]

RT Executables tend to be pretty small, you can see how big exactly by right clicking on the RT Application and selecting "Explore." This opens a file browser at the location of the files that are copied to the RT system, so you can select everything, right click, and select properties to see how large they are.

There are several ways to see how much disk space a remote system has. The simplest is to check the target under remote systems in MAX. On the main page there are some statistics about the system including both disk and memory usage. You can also do it programatically with the get volume info function if you specify the main drive:

https://www.ni.com/docs/en-US/bundle/labview-api-ref/page/functions/get-volume-info.html

As for examples of writing to the RT system disk you should be able to navigate in LabVIEW to Help >> Find Examples (which opens the example finder) and browse to Fundamentals >> File Input and Output and choose whichever one you like. Remember that you will need to run these on the remote system and not on your host computer.

Finally, if you are looking to access the files that are on the remote system you can use FTP or WebDAV.

FTP instructions: https://www.ni.com/en/support/documentation/supplemental/06/ftp-options-with-labview-real-time.html

WebDAV instructions: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YGytCAG&l=en-US