Power interrupted on usb-6229 during recording and data is now not viewable

[Mikea01]

Hi,

I have been recording in Labview SignalExpress 2.5 using the usb-6229 BNC logger. I have been recording on 16 channels at a 1KHz sample rate over a period of at least 7 hours, so as you can imagine a lot of data has been collected. Unfortunately the logger power was interrupted during recording (but not the PC running Signal Express) and although the tdms files are all present, they will not playback. When I drag the log over into the data view area, I get the following error message:-

'The selected log is not prepared for viewing. You must wait until the log has finished recording to view it'.

If I right click on the log before dragging it over, I get a list of options one of which is 'Make Log Viewable'. If I select this, nothing happens at all. If I then right click again, the 'Make Log Viewable' option is gone. Dragging the log over after this step still does not work.

I have recorded other logs of over 7 hours which play back perfectly well.

Should the log files be constantly updated during recording so that if there is a fower failure, data is not lost?

The most important thing firstly though is that is there any way that I can play these logs back or are they gone for good? The .tdms file sizes match those of other file sizes that play OK and have the same 7 hr recording duration.

Thanks in advance

Mike

[Mikea01]

Hi,

has anyone got any ideas on this to help me out please? If someone else has suffered the same problem as me and solved this, then I'd be grateful for your solution. Also, if any experts out there think that there is no way that these files can be recovered to be played back, then please let me know.

Thanks

Mike

[Andrew McL]

Hi Mike,

I am currently looking into whether or not TDMS files can be recovered but I do have a number of suggestions for you to look at in the mean time:

Could you possibly tell me if you have any version of LabVIEW? There are a number of articles which may help you with the TDMS format.

This article gives an overview of the file format and this article gives you an overview of how to use LabVIEW to access tdms files.
The reason I suggested the latter article is that LabVIEW can be used to diagnose whether or not there is any  error with the file. This article gives the error codes for the TDMS file Vis and may help determine whether or not the data file is corrupted.

A further suggestion is to delete the tdms_index file and allow SignalExpress to generate a new file. Please don’t delete this file permanently, just move it out of the directory.

I shall carry on looking into this problem,

Hope this helps,

[Mikea01]

Hi Andrew,

Thanks for your quick reply. Sorry but we only have SignalExpress. Also, just to let you know I have already tried playing with the index file. What I did was to rename it so that it wasn't recognised by SignalExpress. I then opened SignalExpress again, right clicked and selected 'Make Log Viewable'. This time I got the message 'Decimating Log for Viewing'. I started this on Friday afternoon at 1:30pm. When I returned this morning, this process was still ongoing. My log file on Friday started at approx. 2.5G Bytes in size and this morning it was up to approx 4.5G bytes. A new Index file was also being built at the same time. At this point I cancelled the process because the log file size was already 2G Bytes larger than a previous log which had also recorded for the same time duration. Hope this is of some help to you.

Thanks for your help so far.

Mike

[Andrew McL]

Hi Mike,
I have been doing some research and I have made the following observations.

When I unplug a DAQ device mid-way through a sampling period, SignalExpress stops the data acquisition and saves the data file at the last acquisition. From what you have said, this file is the same size as the other data files.

Would it be possible for you to send me your SignalExpress project file? You can add it to the forum thread.

Would it also be possible for you to send me the data file in question so that I could have a look at it from here? We have an ftp server that you can upload it to. It would probably be best to send it late in the day as it will upload quicker.

If you upload files to ftp://ftp.ni.com/incoming. You can do this in Internet Explorer; you will need to click "Page" then "Open FTP Site in Windows Explorer" to be able to upload. The ftp server uses anonymous login.  Also, please send me the file name so I know what I am looking for.

Once you have uploaded the file, if you can add a post to the thread, I will get a notification that the thread is updated and can download the file and analyse it here.

I hope this isn’t too much to ask,

Thanks,

[Mikea01]

Hi Andrew,

I've just spoken to our IT person and he wont let me upload due to the slowish speed of our connection. He said that he would burn a DVD for me though and I could also put the project file on it too. I would then need a postal address and I could get it sent today and you would still have it by tomorrow.

Sorry about this, but I hope a DVD will be OK.

Mike

[Andrew McL]

Hi Mike,

Here is the link to the Address. If you add my name (Andrew McLennan) to the front as well, that should ensure it gets to me.

Thanks,

Andrew

[Mikea01]

Hi Andrew,

the disk is on the way to you. Hopefully you should receive it tomorrow.

Thanks

Mike

[Andrew McL]

Hi Mike,

I have received the disk and shall look at the problem asap. 

Thanks,

[Andrew McL]

Hi Mike,

I believe I have been able to recover your raw data. I will send you another DVD with all of the files that I have updated. There will be a number of additional steps that you will need to run in order to get the recovered data into SignalExpress but I shall give you a file on the DVD with these instructions and any additional install files. Unfortunately, I am not sure if you will be able to include it into your original project but it should still give you all of the information that you require.

Would it be okay for me to send the DVD to the address that you gave in the DVD?

Thanks,