tdms marker

[GlenS]

Hi,

I'm using the pause trigger to read from the DAQ input buffer and write to a TDMS file according to the rise and fall of a TTL trigger.  I'd like to be able to separate each section of data after the collection is finished so I was wondering if there is a way to insert a marker of some sort in the measurement file that I can seek later, or is there a better way to do this?

[NAKeel]

Hi Glen,

When you write data to a TDMS file a header file is written with each batch of data.  You can then search by header data.  The following link describes how the header data and index files are written in the TDMS files:

Why Are My TDMS Files So Large?

http://digital.ni.com/public.nsf/allkb/63DA22F92660C7308625744700781A8D?OpenDocument

[Herbert Engels]

Glen,

you could create a new group with each batch of data. If you use waveforms, every channel will then automatically have a correct start time stamp and delta t attached to it as properties. However, if you create thousands of groups, that will create some overhead in terms of memory footprint and writing performance.

An alternative solution would be to store an additional channel that could e.g. store time stamp or batch number or something.

Hope that helps,

Herbert