error 42 when creating a zip file

[zener]

Hi,

I am getting an error 42 when I try to create a zip file in Labview.  I am deploying to a Cfp module.  I try to create the file first, then my loop will close a data file when it gets to 1 meg and add it to the open .zip file and open another data file.  

I cannot test that part till I can open a zip file first.  Seems I don't know how to specify a path? My path I use for the data file is "c:\k2XXXX.dat" with XXXX being the current clock ticks.  And the zip path I am using is "c:\K2data.zi"  Why doesn't this work with the create zip file VI?  I am using the string to path vi.

Thanks

[zener]

Error above.  The filename is actually "c:\K2data.zip"

[NI-Bob · Accepted solution]

Hello Zener,

Thank you for contacting National Instruments!  I have seen this error before when using the ZIP VIs on a cFP controller.  Unfortunately, this error occurs because the ZIP VIs are Windows dependent and are not supported by the Real-Time OS. We are working to make these changes to the real-time functions palette.  I do apologize for this inconvenience.  If you do need to utilize the ZIP VIs then you should be able to transfer the data to a host computer and then call the ZIP VIs from there.  If you have further questions about this issue please just post them here and we will assist you.  Have a great day!

[zener]

Thanks for the info.  Problem is, I want the controller to operate stand alone, and capture a large amount of data. 10 parameters @ 20 hz.  for about 24 hrs.  ~74 Meg of data.   Any Ideas on how I can accomplish this without using an external computer? 

I can write a compression algorythym, save the data, and de-compress at a later date perhaps?  Is there a vi already available for this?

Thanks

[NI-Bob]

Hello Zener,

There are a few different options that you can look into when constrained by memory.  First of all, which cFP controller are you using?  I know that the cFP-2220 has options for removable CompactFlash and USB storage that may assist you in your application. 

If you are specifically interested in file compression, I have heard of some customers using the zlib library.  From the customer comments below it sounds like you will need version 1.1.4 in order to work in Windows XP.  Also, here is a forum post that discusses the positives and negatives of the zlib library and some other possible options.  If you do have any other questions after looking through this information please just post back here.  If you have more questions about different file compression options I would possibly create a new forum to get more feedback from what other LabVIEW users have tried as well.