File name convention when accessing NI 9802 from RT Host vi.

[Stephen_@_HII-Ingalls]

I have a question regarding the file name convention to use when writing files to a NI 9802 module. 

Just to note, I'm using a 9014 controller with a 9104 chassis, LabVIEW 8.6 RT/FPGA, and NI-RIO 3.0.

I've read a post regarding the subject.  The post says to use the DOS 8.3 naming convention in the form of "CRIO-X##.BIN".  All uppercase letters.  See http://digital.ni.com/public.nsf/allkb/D15720EB0F60FAC58625732700070081.  (Also, I guess from reading the post that you're limited to 255 files per directory, maybe?)  The built in example for writing data to a file on the 9802 from a RT Host vi shows using "Example.txt" as the filename.  However, the built in example for writing directly to the 9802 from the FPGA using Methods does use the "CRIO-X##.BIN" convention.

I guess what I'd like to know is this:  Does writing data to the 9802 from the RT Host vi require using the "CRIO-X##.BIN" convention (to be efficient, anyways)?  I was hoping to use filenames that actually had the date/time in the name (e.g. Node2_09_04_59__10_30_2008.txt).  Does the "CRIO-X##.BIN" convention (DOS 8.3) only need to be used when writing directly to the 9802 through Method Nodes?

I'm not writing lots of data real fast, but rather, recording some data for long periods of time (many days).  Additionally, I plan on writing the data as text.

Any info would be appreciated.  Thanks.

Stephen

[RossH]

Hi Stephen,

The CRIO-X##.BIN naming restriction comes only from the limitations of the FPGA.  We sometimes encourage people to follow this naming convention only because we don't want people using RT to suddenly realize they'd now like to use it from FPGA and now they have to rename all their files.  If you are only using 9802 from RT you can names your files anything that's valid in the FAT16 filesystem.  This includes names that are longer than 8.3.

The reason for all this is that in the FPGA case, the entire filesystem must be implemented on the FPGA.  We have to make lots of trade offs for FPGA space.  When you use the 9802 from RT the filesystem is implemented on the controller and is a more complete implementation.

You are also correct that from FPGA you are limited to 255 files.  Post again if you have any other 9802 questions.

Ross

cRIO R&D