Problem using two USB drive on compactrio 9081

[Infodeck1]

I am logging measurement data to a usb drive plugged to one of the the four USB ports (U:). The program will start logging to another usb drive plugged in to the second USB port (V:) once the first usb drive gets filled up.

Everything works fine until I purposely turn off the compact RIO and when it reboots , the first usb drive retains the letter U: and also V label. The second usb drive can now be accessed via w: drive. I would have thought the first drive should only be accessible using the U label and the second usb drive by label V:

I wonder if I could get help with this

[AudioVideoDisco]

Hi Infodeck1,

Thanks for posting.

This is indeed some interesting behaviour. What model of cRIO are you using in your application?

There is an application called the Real Time Application Deployment utility that you may be interested in and may potentially be a workaround for the behaviour you are experiencing - depending on your application. See the link below for more information on this.

Replication and Deployment (RAD) Utility - http://zone.ni.com/devzone/cda/epd/p/id/5986

FTP Transfer of Files between Host and Real-Time Targets - http://digital.ni.com/public.nsf/allkb/571113C2CE05998E862574E8006005A2

Would the RAD application for imaging your real-time controller be useful in your application?

Regards,

Paul

[Infodeck1]

Hi Paul,

The compactRIO is the NI 9081RT , I am using the scan mode for programming it. My application writes measurement data to a first usb disc, if that disc gets filled up, the program would start storing to the second disc. My program looks for the drives letters of these USB storage discs before storing data.

I was hoping once the two usb discs are plugged in, they are labelled U: drive , V: drive and they retain their respective drive letters with reboot of the compactRIO after power loss.

I am not sure what the RAD is but I am looking into to see how that would be useful.

Thanks

[AudioVideoDisco]

Hi Infodeck1,

The RAD utility can be used to create an image of a Real Time controller with a startup VI.

After you create your application and deploy it to the Real-Time controller (using the correct drive names), then take an image of the real-time system. After you reboot the controller simply push this image back on to it and it should retain the same drive names as when you took the image.

Kind Regards,

Paul