NI-272x Reference VIs Error

[y.emre]

Hello everyone,

I use PXIe-2727 programmable resistor module with NI-272x Reference VIs (like Figure 1.).

                                      Figure 1.

I was using it before without any problems. However, the error in Figure 2. has been occurring recently.

                                      Figure 2.

The related VI and error code are as shown in Figures 3 and 4.

                                      Figure 3.

                                      *Figure 4.

When I checked the input and output connections of the SubVIs, I did not see any problems. Would anyone please tell me what is going on and how to solve it?

Additionally, how can I create a VI with the NI-SWITCH toolkit or different way that directly outputs the entered resistance value? Because I have a project that I tested by increasing the resistance value between 0-2000 ohms.

Thanks in advance and good work. Best regards.

LabVIEW 2024 Q1

* https://www.ni.com/en/support/documentation/supplemental/12/ni-272x-overview.html

[Kyle97330]

I've not used these VIs nor do I have them to look at so this is based just off of screenshots...

Regarding the error, the error shown is one I might expect to see if one of the two following things has happened:

• The device or session reference might have been closed before it reached this VI
• The device or session reference passed into this VI might have been a "default" value from somewhere

It looks the VI that generates the error has two inputs, "session handle" and "semaphore".  I'm not sure about "semaphore" though, it might be an output or an internal-only control.

At any rate, I would track the reference wire(s) leading into this VI and see if there is any place they might have been either closed or set to default values.  Common places for default values to come accidentally are:

• Event structures, which have "use default on unwired" on by default on all outputs
• Diagram disable structures, same issue
• FOR loops that might run 0 times and the reference wires pass through them instead of around them or through a shift register