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Raw (Unscaled Data)


elsears

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Is there any way for SDR to export (and/or store itself) raw (unscaled) values/data into ascii txt files?  I've recently run into cases where discrepancies between commissioning sheets (and different versions of these commissioning sheets) and file-specific values of the scale factor and offset are causing me to re-run massive bulk imports.  That is fine, except that I have a separate database as well for manipulating the data in other ways; and when this happens I have to re-run that process as well. 

 A perfect fit, for me :), would be to store the data in my own database in an unscaled manner, and then apply the scaling on-demand; based on the latest agreed upon scale/offset values.

 

Thanks,

Edward

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  • 4 weeks later...

Personally, my approach has been to leave the loggers set to factory defaults for the sensors (at least the "normal" ones - anemometers, vanes, temp).  That way, you don't have to worry that someone tweaked the settings in the logger, or got them wrong.

As to how to "unscale" the data, it's my understanding that you just subtract the offset and then divide by the slope.

The SDR does   value * slope + offset = scaled value.

So the inverse would be     scaled value - offset / slope = value

By storing the values using the default values in your database (either unscaled or the "normal" values for slope/offset), you can always back them out and then re-scale as necessary.

I'm doing this right now for one of my clients - we did post-calibration of some anemometers and we're working on formulaically applying the change in slope/offset to the data (assuming that any change in calibration occurred over the life of the anemometer).

George Friend
President
Prodigium, LLC
george.friend@prodigium.us

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  • 2 weeks later...

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