use reference trigger for cyclic recording data

[HW_Autodesk]

Hi, Jim:

I already use the feature 'Use next available name'. It ONLY works when I stop the whole program! I've also tried all the other options available but none of them working for my purpose. For example, the case structure only allow one file to be recording the 'enable' periods' data but not in several files format.

If you still remember what I am trying to do, I need recording each cycle as ONE file within the run, which means each cycle file closed without interrupting the whole LV's running.

So, would the 'Write to measurement file' VI be able to do that? If the answer is 'No', then, are there some ways to close the file given the whole program is still running?

Regards

HW

[jschwartz]

Hi HW,

One thing you could do is to write to a series of tdms files with the timestamp as the file name.  I have attached an example that will show you how to do this.  If you want to read tdms files, you can use the Read from Measurement File.vi or you can use the Read TDMS File.vi in the Example Finder.  You can find the Example Finder at Help >> Find Examples. Once the Example Finder opens, search for TDMS and you should be able to find the Read TDMS example. 

[HW_Autodesk]

Hi, Jim:

It seems that we're going to be on the right track now. I can use my trigger signals to replace the TF input (see my attached VI).

However, I found the problem - Err118 with TDMS Open.vi, indicating that the supplied folder path does not exit. I check your original VI which has the same problem.

To my understanding, the sample shows a specified path plus would create a new timestamp file each time when the condition is true, resulting in a series of files.

Would there be something wrong with the 'Build Path.vi'? Please feel free to edit my attached VI.

Regards

HW

[jschwartz · Accepted solution]

Hi HW,

I wasn't able to reproduce this.  Make sure that you select the correct folder.  Take a look at the following screenshot:

Make sure that you select the current folder for the TDMS write.

[HW_Autodesk]

Hi, Jim:

Fantastic, it's working properly. I also downloaded the TDM_excel_add_in to open the file in Excel.

Just one more question - in your sample, there is an 'implicit' time column to show the starting time however it only shows the channel data without implicit time in my recording file.

I tried 'TMD Importer Configuration' but it seems I already choose all the available properties. How can I have the implicit time in my TDM files?

Cheers

HW

[jschwartz]

Hi HW,

I'm not sure if I understand what you are asking.  Could you post a copy of the TDMS files so I can compare the headers?  This may be an issue with the type of data being fed in.  Mine is dynamic data (which is the output from the express VIs) and your data is waveform type.  

[HW_Autodesk]

Hi, Jim:

I got problems to attach the file .tdms or .xlsx so what I can do is to show you the png file to illustrate.

Hope that will make it clear enough - my recorded data only got two channels's data WITHOUT 'implicit' time.

Cheers

HW

[jschwartz]

Hi HW,

I have verified the behavior.  It appears that there is a difference between the simulate signal and the actual DAQmx VIs.  This should be ok, however, as you have the starting time and dt which you can get your time information from.

[HW_Autodesk]

Hi, Jim:

Thanks for your help. I've polled one signal for the whole cycle - from 'start' to 'stop'; and realized the process to record each cycle file during the continuous run.

Two things I am still try to get: 1) Implicit time. Will there be an internal or external clock signal I can use to record together with my data channels?

2) How can I count the trigger signal at the same time, which can be used as the reference cycle no. for my files? I got conflicting message saying 'can't use physical channel for virtual channel input' when I used the counter edge from DAQmx Create Channel - CI Cnt Edges. What I need is just a counted no. from my digital triggerring signal which I can add to my file name instead of time string.

Your assistance is highly appreciated!

Best Regards

HW

[jschwartz]

Hi HW,

If I understand correctly, you want to count the number of files saved?  You can see below for a way to count the number of times you are saving a file.

As for getting implicit time, do you just want a column to show the elapsed time since the beginning of the acquisition? Or are you worried that this is not going to display properly?