TDMS Data Logging - Waveforms & XY data

[_aniket72]

Hello Everyone,

I am measuring data of two different types of data

1. Waveform (t0, dt, Y)

2. XY graph (timestamp [array], Y[array])

My use case is:

1. Channels (10 channels) with waveform data has sample rate 1kHz, which acquire data as waveform. (DAQmx AI channel)

2. Another channels are (100 variables) OPC-UA based, which acquire data on event, and returns data in timestamp & value format.

OPC-UA variables changes its value very rarely.

3. I don't want to convert OPCUA data to waveform, since it will acquire more space.

I want to log both data in same TDMS file & analyze/veiw in DIAdem.

How should i achieve this?

BR & Stay Healthy,

[Brad_Turpin]

Hi Aniket,

I suggest you put your 10 waveform channels into one group in the TDMS file, then create a new group for each separate X=Time channel that you have in your XY channels.  In the simplest case that all 100 Y channels use the same X channel, then that would give you a second group with one X=Time channel and all 100 Y channels in it.  In the most extreme case that would result in 100 groups with exactly 1 X channel and 1 Y channel in them each.

In LabVIEW you can easily append X values and Y values one at a time to the respective channels in the group(s) after the first one, as they appear on the OPC bus.

Brad Turpin

Senior Technical Support Engineer

National Instruments

[_aniket72]

Hello Brad_Turpin,

Thank you for your time.

Actually I don't want to share X = Time Channel for 100 OPCUA channels.

Because, some OPCUA channels updates its values very frequently and some channels very rarely. Its due uncertain behavior of events from PLC.

My test system runs for 1-2 months. (testing)

It is okay to have 100 X Time Channels & 100 Y channels. But end user needs to compare/plot/analyze both type of channel data in single view in DIAdem.(AI waveform and OPCUA data).

Please suggest TDMS grouping hierarchy.

Currently TDMS hierarchy is as follows for AI channels.

Root = Test Name

Group 1 = Track 1

              AI Channel 1

              AI Channel 2

Group 2 = Track 2

              AI Channel 3

              AI Channel 4

Group 3 = Track 3

              AI Channel 5

              AI Channel 6

Group 4 = Track 4

              AI Channel 7

              AI Channel 8

Group 5 = Track 5

              AI Channel 9

              AI Channel 10

BR & Stay Healthy