Expected length of tables from .dat and .sen files?

Hei,

I was measuring a water flow using vectors. The measurements were taken at 8Hz. Thus, I expected the number of rows within the .sen file to be 1/8 of the number of rows within the .dat file, because the .sen file would have one row per second, while the .dat file should contain 8 rows per second.

When I multiplied the number of rows within the .sen file, I ended up with 12 more rows, than there were within the .dat file.

That is a problem, because I will have to relate entries of both tables with each other.
The question is, which rows within the two tables contain data acquired simultaneously?

My idea was to relate the first 8 entries in the .dat file to the first entry in the .sen file, as both represent data obtained in the first second of the measurements. Unfortunately, I am not absolutely sure, if that is right, as the tables aren't having the same number of rows after multiplying the number of rows of the .sen file with 8...

What data will represent measurements taken simultaneously in the two tables?

Best regards,

Lars Gansel

Hei Lars,

For the sensor data one measurement is taken at the beginning of each burst, before the velocity measurement starts. Since the sensor data are taken in between the velocity data you may or may not get one extra sensor sample at the end of each burst as well, depending on the exact number of velocity samples you have configured. For 8 Hz, a good match will be to discard the first sensor measurement in each burst and from then on align the next sensor value to the first eight velocity samples and so on. You can find more information here.

Best regards,

Sven Nylund