VI Tree

[Bob_Albern]

This is a basic driver development question. Some drivers have a VI Tree.vi in the instrument driver library and some do not. It seems to be associated with drivers that are implemented using VISA. What is this for? In the drivers that have this, all the connections seem to be recommended.  For drivers that do not have a VI Tree.vi, the connections are a mix of optional, recommended and required. As I develop a driver for an instrument, what are the ramifications of using the VI Tree.vi? What does it buy me if I use it and what will be lost if I don’t? Can I not use it if I develop a VISA based driver?

Thanks,

Bob

[thehobbs]

Hi Bob,

A VI Tree is a top-level VI that is included with an instrument driver to display the driver's API.  It serves as one place that a user can go to see the entire layout of the driver.  Comments and notes can be added to the VI Tree indicating things like VI depencencies on other VIs or VIs that only supported particular models of a product series.  The layout of VIs in the VI Tree should match the layout in your palettes.  A VI Tree can be included in a driver regardless of if the driver is VISA based, although I strongly recommend that you implement your driver with VISA.

Teminal connection requirements are independent of a VI Tree.  The LabVIEW Instrument driver templates:

https://www.ni.com/en/support/downloads/instrument-drivers/tools-resources.html

are all VISA based and include VI Trees.  For these templates all of the VISA resource name controls are required.  This results in the VI Tree having a broken run arrow, but this VI is not intended to be executed.  Most of the other inputs are recommended.

The Instrument Driver Guidelines:

https://www.ni.com/en/support/downloads/instrument-drivers/tools-resources/instrument-driver-guideli...

provide more details on which connections should be required, recommended, or optional.

Please share your driver with the rest of the LabVIEW community by submitting it to the Instrument Driver Network.

Jason