How do I append a new custom property to an existing Channel within a TDM File?

[cbauer]

I am trying to append a custom property to an existing Channel within a Channel Group using the Storage VIs. I keep getting an error that says "-2550 This property does not exist." I am able to change existing properties with this method, but not add new properties. Thank you in advance.

[Scott Y]

I would like to direct you to this document on our web site:


There you can find the following note:
"In LabVIEW the storage VIs are found on the file I/O palette; however, if you intend to use the custom properties VI shown above in Figure 4, you find this VI in Storage.llb found at C:\Program Files\National Instruments\LabVIEW 7.1\vi.lib\platform\storage, the VIs name is _saveProperty.vi."

Scott Y
NI

[cbauer]

I am using that VI. It is working great when I am adding the Channel for the first time. The problem is if I have created a Channel at a previous time, then later I run some queries to find this Channel's refnum, then I try to add another custom property, I get an error that says the property does not exist. this is where the problem lies. How do I add a custom property to and previously defined Channel?

Thank you,
Chris

[Scott Y]

Hi Chris,

Would it be possible for your to post a small example that demonstrates this error?

Thank you,

Scott Y
NI

[Phil Rawlings]

Does anyone have any example code that can show this working? Whatever I seem to try, I cannot get LabVIEW to add cutom properties to either file (what I want to do), channel groups or channels.