Jim,
I don't now if your approach can work (e.g. the Fieldpoint driver allow it), however my way to solve that problem:
Write one vi that will do the Fieldpoint handling (Open,close,IO) and that run in its own treat(FPhandle.vi).
For communication you can use VI-Server (to start that vi and read a handle) and named queues for the data transfer.
A new.vi will load the FPHandle.vi with vi-server and look at an status-indicator telling if it's already running/FP-device opened etc.. If not: run it in the background
FPhandle.vi listen to a named queue ('FPhandlecommand') with a data type (cluster) including the string (name) for your return-queue ('new-return') and a command string or better a strict type defined enumerated (nice if you want to add new commands later)
You can/should collect a list of return-queue names and remove them from that list if they send you a FP-close command. When the list is empty you can really close the FP connection.
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
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