writing signals to lvm file - format issues

[jim v]

hi all, i'll try to keep it short.......

i'm using lv8.0 to read signals from 4 sensors and, if necessary, save the signals to a .lvm file.  i'm using the "write to measurement file" express vi to save the file.

after saving a batch of data (say 5 seconds at 2000 samples/s) i open up the .lvm files (using excel) and things look normal.  the 1st column is blank, the 2nd column is sensor #1, the 3rd column is sensor #2, etc.  so far so good.

as i scroll down thru the data, new columns begin to appear.  at row 1001, 4 additional columns of data appear.  at row 2001 4 more columns appear and this continues until the end of the file.  i've tried various combinations of options in the express vi dialog without any luck.  i've also tried the "write to spreadsheet file" standard vi and get the same problem

background - this is part of a larger vi that reads and saves signals from other sensors as well.  i have no trouble saving those signals in the format i want.  could the two write to file vi's be competing in some way causing this trouble?

thanks for any help

jim

[andre.buurman@carya]

A piece of sample code and/or screenshot of the code would help solve the problem. Also a simplified view of the generated file and expected file would help.

[jim v]

okay, i've included two screen shots -

1 - the first is just an image of the code (well, the part of the vi in question - the entire vi is too big to get on one screen).  this case is the "save data" case.  the other case (not shown) just passes the data thru.  if the entire vi would help just let me know..

2 - shot of the data file.  note how the first column is the empty and columns 2-5 are the data (this is good).  and then at row 1001 the data starts getting written to more rows.  this continues to happen at intervals of 1000 rows.

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andre.buurman@carya wrote:
A piece of sample code and/or screenshot of the code would help solve the problem. Also a simplified view of the generated file and expected file would help.

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[andre.buurman@carya]

You should look at the output of the last build array before you write to file. Check the array for each iteration.
Do you recognise the extra data written at row 1001? (Also written in row 1?).

Addition: Screenshots can easily be uploaded via de forum website "Submit post->Add attachment".


Message Edited by andre.buurman@carya on 11-23-2007 09:15 PM

[jim v]

i've found the problem.  if you look at the images above, you'll see i've wired the output of the build array vi to the write vi.  this means that every iteration all the data (not just the current batch) gets written.  this explains all the extra data popping up unexpectedly.  i can actually save data now  🙂

jim