File Error

[jyang72211]

See attached code.

First, run 2.png to the reference into the FG and write a header to the file.  After that I write to the file with 1.png. I get the follwing error

LabVIEW:  An input parameter is invalid. For example if the input is a path, the path might contain a character not allowed by the OS such as ? or @.

Why is that?

[altenbach · Accepted solution]

When the VI stops, the reference becomes invalid. It gets closed automatically as part of the cleanup operation when the VI stops running.

You need to keep the VI running to keep the reference valid. As proof, place a "refnum to path" in the write case and place an indicator on the output. You'll see <not a path>.

Redesign your program.

[jyang72211]

Thanks.  This is what I need.  I thought of that possibility, but I guess I didn't test it detail enough.  That ref to file is pretty useful.  I didn't know about that.