Double datatype in tdm which is converted from tdms

[MetalPenguen]

Hi all,
In short, to be able to delete channels and groups from a tdms file, I convert the file to a tdm, delete channel or group by making use of storage VIs, and convert it back to tdms. The problem is, when tdms is converted to tdm, double data types (64-bit) became single (32-bit) types. Original tdms file has doubles in it, but tdm and resulting tdms files have singles.
Attached VI does things I mentioned above. After running it, I open tdms-1.tdms in Excel with tdm importer (v3.3.0.0), and datatype is DT_DOUBLE. But in tdm.tdm and tdms-2.tdms files, datatypes are DT_FLOAT. So the question is, is there a way to prevent doubles from being converted to singles?

Note: I have to convert tdms file to tdm, because storage VIs which deletes channels and groups do not work with tdms format.
p.s. I'm on LV2011.

[Mavis · Accepted solution]

Hi,

This is a known bug, CAR 399895. We'll fix it in future.

In your LabVIEW, you could try changing the following VI.

\\vi.lib\Platform\storage\utility\_DP2TDMData.vi, in the "DT_DOUBLE" case, please select Float64 instance.

Hope this helps,

Mavis

[MetalPenguen]

Hi Mavis,

I've made the change you suggested, and problem solved. Thank you!

I am going to build an application, and I guess, my built application will have this altered code. If not, please let me know.

Regards.

[Jeff-P]

CAR 399895 discussed in this thread has been fixed in LabVIEW 2013. For a more complete list of bugs fixed in LabVIEW 2013, check the LabVIEW 2013 Bug Fixes. You can download an evaluation copy of LabVIEW 2013 at http://www.ni.com/trylabview/ or if you have an earlier version of LabVIEW installed and an active SSP subscription, you will be able to download the latest version of LabVIEW through NI Update Service.

Jeff Peacock

Product Support Engineer | LabVIEW R&D | National Instruments