Running cFP embedded with multiple comm resources (cFP-18xx)

[Jason Stallard]

I am expanding my in-vehicle datalogging application to take advantage of the lowcost
backplanes (cFP-18xx).  The goal is to allow the user to add any number of these devices
to the system and the logger (cFP2x20) will discover the expansion boxes.

In MAX I configure the logger with a comm name of cFPDL and the cFP-18xx as Expand_1.

The problems I'm having is when running embedded, the comm res names do not get
saved.  Using FP.getinfo vi's I can discover the comm name of the cFPDL (MAX default though)
easily enough, however there is no information for the expansion module.  Discovreing the
devices shows ALL modules (both 2x20 and 18xx), and makes no differentiation between
what is on the 2x20 or 18xx.  Which makes channel collection, scaling, and logging impossible.

Even though it's not recommended, I can parse fpBank and fpRemote easily enough, but
I'm not sure I can create tags in the manner I would like...which is create refs to "all" for all
modules on the 2x20 first, then "expand_1", then "expand_2"...and so on.

My constraints are first, the 18xx backplanes have no intelligence.  Second, I cannot use
networked variables (PSP) because some of our controllers are 2020's and do not have
the memory or CPU to run the client/server.

Does anyone out there have any suggestions as to how to approach this?

[Jason Stallard]

Well, this is what I've come up with.  If anybody
has a better idea, please let me know.

[Nadim R]

Hi Jason,

Although parsing through the .ini files for Fieldpoint is discouraged and unsupported, I do believe it will benefit in your application.  Looking at the example, I did notice that you are parsing through the .ini file and creating tags for each channel you want.  Are you experiencing any problems with your solution? If so, you may want to post your example so that others and myself can test your VI.

Regards,

Nadim
Applications Engineering
National Instruments

[Jason Stallard]

The configuration as shown in the screen capture works, but like we said, it's not supported by NI.
My preference would be to use the FP vi's to 'discover' what FP devices are on the subnet, and
what modules in what slots are connected to the FP controllers, eliminating the need to parse
fpBank and fpRemote.  The problem with the way FP stores the MAX configuration, I cannot
determine what is the "local" logger, and what is a "remote" expansion along with what I/O belongs
to which using FP get info.

An alternative would have been to use RT-Ping, however the cFP-18xx devices are not RT controllers
and do not respond to the ping request.

Perhaps this something be added to the suggestion box to allow for dynamic FP device discovery
and allow unique resource naming without using MAX(windows)?

[Nadim R]

Hi Jason,


Thank you for the reply.  I agree that this functionality would be extremely useful.  I would highly suggest you file your product suggestion here.  That way, R&D will have some customer feedback as to what functionalities should be added for furture versions of the driver.

Regards,

Nadim
Applications Engineering
National Instruments