distance check

Hi

For the Vectrino with firmware, I'm wondering what the distance check feature is actually measuring...is it the distance from the probe head to the bottom, or from the trasducers to the bottom?  I also don't seem to be getting very accurate measurements of distance when I do the distance check. The values bounce around a fair amount even though the probe head is fixed to a stand, and the readings don't ever settle on/at zero, which I think would indicate that I'm measuring right at the bed. Do I need to have the edit configuration setting at 10hz (a value I read off the help manual) for this feature to work properly?

Thank you,

Lindsey

Hi Lindsey,

Distance Check is using the the same output of the Probe Check function, but applying a peak locating algorithm to determine the distance to the bed from the central transducer. For the distance to the center of the Sample Volume subtract 5 cm from the reported distance. If you'd like to know more precisely the location of the Sample Volume for your probe head, please use the method outlined in this thread: http://www.nortek-as.com/en/knowledge-center/forum/velocimeters/270676734

If you are having problems with Distance Check there are a few things to try. First, please make sure you using the most recent firmware appropriate for your instrument. There have been improvements made in the Distance Check algorithm and it is generally quite robust. You can download the most recent firmware here: http://www.nortek-as.com/en/support/software Note that if you have the Plus (+)  firmware, you'll need a license key to install it. This can be obtained from your sales representative and they will need your probe and body serial numbers or your original order number. This information is available from the Vectrino software in the main data window.

I always like to check my distances with a physical measurement and against the Probe Check output. This gives you a couple of ways to gauge the quality of your measurement. The "Quality" field when running a Distance Check should be over 100 and typically will be several hundred. If you don't believe the measurement or there's erratic behavior, start a Probe Check and see if there is anything odd going on in the received signal. Odd echos, grounding problems, and several other things can result in problems with the Distance Check. You should see a clear, sharp peak in the return signal strength at the boundary in all four beams.

Approximately how far from the boundary is the probe head mounted (distance from central transducer to boundary)?

P.J.

Hi P.J.

Thanks for the information. I'll try the method outlined in the previous post. I'm trying to sample at <1cm from the boundary in a velocity range from quite slow (10cm/s) to relatively fast (100cm/s).

Lindsey

Previously Peter J. Rusello wrote:

Hi Lindsey,

Distance Check is using the the same output of the Probe Check function, but applying a peak locating algorithm to determine the distance to the bed from the central transducer. For the distance to the center of the Sample Volume subtract 5 cm from the reported distance. If you'd like to know more precisely the location of the Sample Volume for your probe head, please use the method outlined in this thread: http://www.nortek-as.com/en/knowledge-center/forum/velocimeters/270676734

If you are having problems with Distance Check there are a few things to try. First, please make sure you using the most recent firmware appropriate for your instrument. There have been improvements made in the Distance Check algorithm and it is generally quite robust. You can download the most recent firmware here: http://www.nortek-as.com/en/support/software Note that if you have the Plus (+)  firmware, you'll need a license key to install it. This can be obtained from your sales representative and they will need your probe and body serial numbers or your original order number. This information is available from the Vectrino software in the main data window.

I always like to check my distances with a physical measurement and against the Probe Check output. This gives you a couple of ways to gauge the quality of your measurement. The "Quality" field when running a Distance Check should be over 100 and typically will be several hundred. If you don't believe the measurement or there's erratic behavior, start a Probe Check and see if there is anything odd going on in the received signal. Odd echos, grounding problems, and several other things can result in problems with the Distance Check. You should see a clear, sharp peak in the return signal strength at the boundary in all four beams.

Approximately how far from the boundary is the probe head mounted (distance from central transducer to boundary)?

 

P.J.

I used the method described to get the exact position using the terminal emulator, and the hex. value...which is reading 3f 00. Is there some sort of error since I'm getting a letter in my output?

Nope, the letter is because this is in hexadecimal format and in addition to 0-9, the letters A-F are used as digits. If you have Matlab, use the function hex2dec to convert this to a base 10 number, I got 63. Remember the byte order is reversed from what you normally read, so the Vectrino is sending this with the "3" first and the "6" second essentially, or put another way, read right to left instead of left to right.

P.J.