Viewing a TDMS File_Advance level

[Muraliaish]

Greeting to everyone in this community.

I am currently trying to build a data logger . I am using a oil temp sensor using VISA Com port I have made connection with the sensor. I can get the measurement and write in a TDMS File. The problem is viewing TDMS file. 

Following are my criteria to view the file:-

1. I  wish to open the file while the labVIEW is running.

2. I  dont want to open in an excel sheet, with the plugin provided by labVIEW.

Things which i have tried:-

1. Multicolumn list box: This works nicely as per my need. But once my TDMS file has larger than 1000 values then Multicolumn listbox says no memory to show.

2. TDMS Viewer: This too works perfect when the file is smaller. When file is bigger it takes longer time (more than 5 min)

My file contains 16 columns and rows 2000 in an avg(depending on the duration of logging it may reach 1lakh)

So I need an idea or sugession to view my bigger TDMS file faster and during runtime in labVIEW.

[YongqingYe]

Hi MuraliSri,

Which version of LabVIEW are you using? And if it takes a long time to open the file in TDMS Viewer, maybe one of the things you could have a try is to defrag this TDMS file firstly by using TDMS Defragment. Please feel free to let us know if there's any more problem. Thanks.

Yongqing Ye

NI R&D

[Muraliaish]

Thank you so much for your reply. Labview version 10.0.  Is there any posibilities of opening the larger TDMS file in Multicolumn list box? Or is there any substitute to multicolumn list box? I have tried opening smaller TDMS file using multicolumn list box. 

SInce I am making following operations-.

1. Opening a TDMS file: whcih can be viewed in a multicolumn list box

2. Selecting the parameters and the rows To make the Graph.

I really need some help  openning the larger TDMS file in Multicolumn list box  which should nt take longer time.

Here is the front panel of multicolumn list:-

[YongqingYe]

If as you mentioned, your file contains 16 columns and rows 2000 in an avg, then it should not be a very large data set. But if you really want to display a very large data set in the multicolumn list box, then maybe you need to do some optimization. TDMS File Viewer also has a multicolumn list box and we have done the optimization in recent version of LabVIEW. The general idea is just to read out the necessary data values from a TDMS file and display the data in the list box, and when users drag the scroll bar, we then read again from the TDMS file for the new data values. Maybe you also have to do the similar optimization in your code.

[Muraliaish]

In which version of labview have you made the optimization? I am planning to get new  LV 2014 in a week. Which memory does the multicolumn list box uses to display the values? 

Let me try making optimization while reading TDMS using multi column list box. By the way do you know what is the highest limit or rows which a MCLB can support?. I searched internet and didnt get it.

If you get to know good examples for TDMS MCLB please share with me. Unable to find much resources under this topic.

-Like: generating report from TDMS file.

 reading and writing TDMS file concurrently 

Thank you so much for your valuable reply

[YongqingYe]

We have made the performance optimization for TDMS File VIewer in LabVIEW 2013, later version of LabVIEW also can benefit. You can view TDMS File Viewer's block diagram easily, all the optimization was written in LabVIEW and public to all LabVIEW users.

[Muraliaish]

I have configured the reading by limiting number of elements to load. and I can load all the TDMS file ( 5000 values from a user defined start index ) in faster manner into my Multicolumn list box.

I have found s major disadvantage of TDMS file:- Deleting the channel. One cannt directly delete the channel during runtime. Addingf a new channel is easier but on the other hand deleting is a major issues. I had to convert to tdm --> delete channel/group---->convert again to tdms. Is there any easy way??

Another issue is, hw can i delete a row from  TDMS file during runtime.

Any suggestions to above problems???

Regards

Muralidharan N.

[YongqingYe]

I'm afraid so far there's no easy way to delete a channel of a TDMS file. The TDMS file format is designed for high speed streaming. If you want to delete a channel, the way you described is a workaround.