removing slow roll errors using OAT in LabView 8.5 - help!

[NDJenkins]

I need some help in removing slow roll errors from shaft vibration proximity probes.  The problem is that I need to use a waveform data file containing coast down data, and use it to compensate shaft run-up/run down data in a separate waveform data file.  When I do this, it appears that the signal is not being compensated properly, that is, there appears to be an "angle shift" between the even angle reference and the compensated even angle signal.  Basically, it looks like labview is subtracting the reference data at the wrong angles, resulting in an even angle signal that is noisier than the uncompensated signal.  Any help would be appreciated.  I have attached the code I am using.

thanks,

Neil

[preston_johnson]

can you also provide your datafile?

is the data a run-up or a coast-down?  You might consider changing the reference selector to either initial or final. 

[NDJenkins]

I'm not sure if i can post the waveform data files, as they are about 50 Mb.

Is there anything different I need to do when trying to compensate data stored in these waveform (.vib) files?

Should I read the reference .vib file at the same time I read the .vib file containing the data to be compensated?  Should the r0 of both the even angle reference and the even angle signal be the same?

[preston_johnson]

The important point is that the data from each channel should be simultaneuously sampled. 

You can place the data file on our ftp site, ftp.ni.com, in the folder incoming.  Let us know that it is there, so we can retrieve it.

[NDJenkins]

Files are posted.

[preston_johnson]

I have cleaned up the VI a bit and made one correction.  See the attached new version (8.5.2)

The one major change is to remove the F input on the reset terminal of the resample function.  This causes the filters to be unsettled on their first run.  By removing the input, the VI recognizes its first iteration and resets its filters automatically. 

I also poked around with your data and noticed that you have  a run-up and coast down.  Further, you had started your data file at block 156, and I do not understand why.  This causes the read file to error out which in turn erases the results.  If you are doing a run-up and coast down, perhaps we would want to use either the initial or final blocks (a setting for get the profile) rather than average. 

Let us know your thoughts

[NDJenkins]

Thanks!  It appears to be working now.

Neil