SNR ProblemUp to Velocimeters - single point
SNR ProblemPosted by Mohammad. A at April 24. 2012
We bought a Vectorino+ and I' completely new with it. I did some tests a week ago and all the time I saw an error in the down right of the Vectrino software "data buffer overflow" I searched the Nortek website forum and found that maybe it's vectrino software problem and I should update it.
After a week which I was trying to understand my tests data (and do not work with ADV), I decided to update vectrino software (to 1.20+ from 1.15+) and also beside this I update the Vectrino+ ADV firmware (to 1.31+ from 1.30+) too. But after that, I believe anything goes wrong. When I want to take data my Y and Z2 data are terrible. I really don't know what to do. I just do a "probe check" and attach it here. Also I saw that the Correlations are really good. about 90% but the SNR are really low. about 1! (in all 4 graphs)
Please tell me what should I do. I'm sure between my tests and the update process (which was about one week) nobody touch the ADV!!
Thank you so much
Re: SNR ProblemPosted by Jonas Røstad at April 24. 2012
I am sorry to say that this instrument needs to be repaired. The error is not related to the upgrade of software/firmware.
You will receive an RMA number by e-mail.
I don't understand. Why this happened. Why the correlation is high but the SNR is low. what does it mean? And also why this happened after the upgrade process?
Do I do anything wrong?
What Jonas saw was receiver four is showing a very high and flat response throughout the probe check range. This suggests there is something physically wrong with the transducer. The other three beams also show higher noise levels which is probably related.
This problem is unrelated to the upgrade process. Correlation is high because of the noise problem above, which is correlating with itself (in this case it is not what we would call white noise, but rather some constant signal in the data). This also explains the low SNR, since the signal is almost entirely noise.
Thank you so much for your answer. But I don't understand the reason yet. Could it happen without any reason?!
I'm analyzing my tests right now to understand at which test I saw this problem.
Take a look at the probe head and see if there is any physical damage such as a crack in the blue potting material or a bent receiver arm. This is the most likely cause. There could be a problem internally however that won't be obvious.
Like Jonas said though, the instrument unfortunately needs to come in for repair, and this will be the easiest way for us to figure out what happened.