prevent input physical input channel control reset

[rossu]

For some reason, when a vi is loaded, any daqmx input physical channel controls become invalid if the device is not present (i.e. not turned on). This doesn't happen for output channel controls. Is there some way to prevent this behaviour? On my front panel, I have an array of clusters that define a physical channel, a channel name and the input range (and potentially a few other items). The idea is to make it easier for the user to set up and define the inputs without having to use NI-MAX. Most of the time these don't change, so you would think one could preserve the input values with "make current values default". However, whenever the vi loads the array is disabled - presumably because the input physical channel is invalidated (? a control array of numbers won't become invalid when a vi is loaded). Turning the device back on does not enable things and the array has to be redefined every time the vi is loaded. Annoying. Is there a way to prevent this?

[Kevin_Price]

I suspect you can fix this if you:

- right-click on the physical channel GUI control

- select "I/O Name Filtering..."

- adjust your options as needed (pay particular attention to "Allow Undefined Names"

-Kevin P

[rossu]

Nice idea, but no banana. I didn't know about that option. As far as I can tell the input and output channel controls are identical under "I/O Name Filtering". The default case allows undefined names. I tried playing with it but couldn't find anything that stopped the unwanted behaviour

[Bob_Schor]

I'm not 100% certain I understand your problem/question.  Here's what I do for a USB 6000-series Multifunction DAQ device:

1. Run a sub-VI that enumerates all Device Names found on my system.
2. Searches this list for the particular DAQ device I want to use.  Note that this can return the ProductType as a String ("USB-6001"), as well as the Device Serial Number (a U32 Hex value), should I want to say "I want to use this specific device".
3. If found, go to step 4, otherwise inform User and take appropriate action (which could involve aborting, continuing without DAQ, or waiting 30" for the User to plug the device into the PC).
4. Once you have a DAQmx I/O Reference, you can access its Analog and Digital Channels, configuring them as you wish.  You know the device is there, so you set it up appropriately.

Bob Schor