sort tdms channels

[tda*!]

I am reading data from channels of a TDMS file. The channels are different frequencies which data was recorded. However they are not in order. For example the channels might be arranged, 1 Hz, 2 Hz, 3 Hz, 7 Hz, 5Hz, 4Hz. I am trying to either sort these channels in my file. Or another option would be set and "lock" the channel order in the tdms before collecting data.

[crossrulz]

How are you saving to the TDMS file?  Can you share some code?

[tda*!]

So its a bit complicated. But basically I will call this vi to save data. I input into it different sample rates. So I might call it with input rates in the following order...1Hz, 2Hz, 4Hz, 1Hz, 1Hz, 2Hz, 1Hz, 2Hz, 4Hz, 8Hz, 1Hz, etc. until I am done.

[deppSu]

If channels are logged with different frequencies. Than the total count of the channels diffs according to different frequencies, am I right? If so you can use property "NI_ChannelLength" to sort the channels.

[tda*!]

Each channel will "fill up" once it hits a certain length. So that wouldn't work 100% of the time. I guess I know I could sort the channels, there doesn't seem to be too easy of a way to do it.

[Ryan-OC]

Programatically it makes more sense to me to sort your channels first. You could dynamically check to see if the "channel" is full then increase the length accordingly.

[tda*!]

I'm pretty sure that first data points are being written to each channel with proper synchronization. But for some reason, the order of the channels is getting mixed up when I am writing to them. I assumed that once a channel is added to the file, its place is set. Is there a way to create empty channels in the beginning, so the orders are set?

[deppSu · Accepted solution]

Now I know what you mean. The mixing of channels is because of the "NI_MinimumBufferSize" property which will cache raw data until it reaches the amount you set. 

You are right that once a channel is added to the file, its place is set. Thus, you can try to put a "TDMS flush" right after your "TDMS Set Properties" node. Once channel with properties is flushed to disk file, the place is set.

[tda*!]

Ahhhhh. I thought it might have to do with the buffer size. That did the trick! Thank you.