Oddities with Vectrino+ time stamp

Hello,

I'm using Vectrion software versino 1.15 and three different Vectrionos with the 1.30+ firmware, all running at the 200Hz sampling rate. I stored all the data in the .vno binary format and then used the data conversion utility to create the .dat and .hdr files. When I open the header files and read the text it states that the sampling rate was 25 Hz. When I open the data files in Excel 2007 it shows the time stamp as incremetning every 0.04 seconds, consistent with a 25 Hz sampling rate. However it looks like the data was actually recorded at 200 Hz as the time runs to 2938.72 seconds when in the actual test duration was about 6 minutes (360 seconds). It looks to me that the time increment step is off by a factor of 8 (200/25). Has anyone else come across this issue? Is there some option in the Vectrio software that controls this?

On another note is there some reason the ensemble counter periodically skips values and time steps? I haven't been able to find any documentaion on this.

Jesse

Hello Jesse,

I am afraid I am not able to reproduce this. If you could please upload the .vno file to ftp://ftp.nortek-as.com/pub/incoming/ I will have a closer look at it

Best regards,
Oistein Hurum

Oisten,

I placed two files in the FTP directory one is 20100608102020.vno, the other is 20100608102020.dat that resulted was the result form the data conversion process.

Thanks,

Jesse

Thanks Jesse,

The file converts fine with the Vectrino+ software which supports 200 Hz systems, but not if you use the standard Vectrino sw (max 25 Hz). Unfortunately the software allows you to convert the file without poping up a warning that the data is from a 'plus' system. This will be fixed in the next software update.

Thanks for discovering this

Best regards,
Oistein

Thank you Oisten, that was indeed the issue with the time stamps.

Do you have any insight into why the ensembel counter would skip points? The reason this is a concern is that it eleminates time steps as well. With the file that I uploaded to the FTP site time stamps and counter look like this after conversion 

I know it is only .05 seconds worth of data but I need to have a auditable trail on my data or at least a very good reason why there is a "hole" in the data.

Jesse

Hi Jesse,

The data gaps you're noticing are likely due to a bug with version 1.15 and high sample rates. Did you receive an error in the lower status bar of the Vectrino+ software when collecting data that said "Data Buffer Overflow" followed by a time?

Oistein is working on fixing this, but it's been a tough bug to track down. If you need to sample at 200 Hz and I can send you an older version of the software that will work.

P.J.

The data was acquired using version 1.13 plus, when we were just collecting data but not recording I do remember seeing that warning a couple of times. When data recording was on I don't recall seeing it. When I'm using these ADV's for the actual testing I will be using the polysync version 1.0.17. Does polysync have the same limitations? The test rig we're building that these ADVs will be going in isn't ready so I haven't got the opertunity to test that software out.

Jesse

Jesse,

Polysync should work fine for running three Vectrinos at 200 Hz. I've only used it a couple of times, but have had no trouble with high sample rates. It's odd you saw the overflow error with 1.13 as that's the last version I've been able to identify that didn't have this bug. Thankfully, Oistein is narrowing it down and looks to be pretty close to a fix.

P.J.