Spaces In Property Names

[Hooovahh]

It is a known restriction that DIAdem, and DataFinder coerce spaces to underscores when searching for property names on TDMS files.  The Excel Add-in does something similar.

But the TDMS file structure and API apparently supports reading and writing properties with spaces in them.  So my question is why does DIAdem and DataFinder not support spaces in the name of properties?  This limitation must exist for a reason since if it were a simple fix it probably would have been taken care of years ago, so I'm not asking for this functionality to change just curious.

[Brad_Turpin]

Hi Hooovahh,

The short answer is that the DataFinder and DIAdem expect your properties to be indexed by the DataFinder data base.  Spaces in the property names play havoc with advanced queries-- think "Group.PropertyName=Foo".

The LabVIEW TDMS functions were written to be as fast as possible during streaming, so no validity checks were included in the write process.

Brad Turpin

DIAdem Product Support Engineer

National Instruments

[thoult]

Hi Brad,

Resurrecting this - it's only a month old, but it's still mild thread necrophilia nonetheless 🙂 - is there anything in the settings to disable this behaviour if indexing is not of interest to me?

I ask as I've stumbled onto this feature when trying to tweak a saved NaN value in a LV-generated TDMS before uploading it to an SQL database. On saving, I found the behaviour that Hooovahh describes, plus a few additional properties added. Next time I come across this, having been duly burned this first time out, I'll just do it via LV! 🙂

[Brad_Turpin]

Hi thoult,

There is no way to turn this property name coersion behavior off in DIAdem or the DataFinder.  The Storage VIs, including the Write to Measurement and Read From Measurement express VIs have this name coersion, but the VIs from the TDMS palette do not.  You should be able to use the TDMS Write.vi, etc. and avoid any name coersion in the properties.

Brad Turpin

DIAdem Product Support Engineer

National Instruments

[thoult]

I do indeed use those TDMS VIs regularly with no problems, but thought it would be quicker to just load Diadem and tweak a particular property rather than write a quick VI to update a single field.

Thanks for the confirmation!