Can convert some data types from variant, but not others

[scmave]

Hi Gregory,

TestStand seems to have difficulty with passing variant data to LabVIEW and you can see by the example I've included that we recommend creating a container to pass to the variant datatype to convert to a cluster and pull out the different datatypes from this cluster.

Community: Send Data from TestStand to LabVIEW as a Variant

This other forum post also references an except from one of NI's Product Support Engineers stating that TestStand is limited when working with variant datatypes.

I hope this all explains the limitation and how to work around it!

[Gregory]

Hi Mathew,

Using your example I was able to send a container with a numeric from TestStand to LabVIEW without a problem. However, using a container with an analog waveform gave the same error as before.

The forum post you linked to showed the user having trouble sending a variant from LabVIEW to TestStand. I'll assume I'm running into a similar limitation trying to send a waveform to a variant from TestStand to LabVIEW.

[scmave · Accepted solution]

Hi Gregory,

Looking into this more, it appears that in order for TestStand to send Variants to LabVIEW it has to send them as COM Variants rather than straight LabVIEW Variants. This means that it cannot send the same attributes that are in LabVIEW Variants, which waveform data seems to be depending on. So this seems to be a limitation specifically with datatypes that use attributes in LabVIEW, because TestStand cannot pass them.