Most of the industrial scales that allow location to be specified do it to improve out-of-the-crate accuracy where you might not have a calibration weight/cart/truck available (BTW, calibration carts are not used on the more accurate scales... things like bouyancy of the air in the tires can greatly affect the apparent mass). Most lab scales way to accurate to be able to effectively use a gravity model. They have built in calibration weights (or use external weights) that compensate for such things. I have not tried to see if I can see the tidal effect with my Mettler mass comparator (1 part in 100,000,000 res). I would suspect that it would be swamped by temperature fluctuations and the HUGE effect of air density (the weigh chambers on these beasties lies behind three layers of thermal glass to keep radiation of body heat, etc from stirring up air currents). At that level of resolution you are recalibrating the scale pretty much between evey reading. -----------------------------------------------------------------Mark,
That's very cool that they would model static gravity effects like that. Makes sense at that level of resolution. Do you know of any laboratory scales that also require you to enter the date/time so they can also model the dynamic 0.1 ppm effect on gravity of lunar/solar tides? /tvb ********************** Funny, Anyone out there that remember "True weight, no springs", and for a penny you also get your horoscope. Load cells have taken a big step backward. They use springs and therefore are measuring weight and not mass. This is why they need to be calibrate for the location they are at. Gravity can vary by more 0.1% from location to location, so a spring scale needs to be calibrated for a given location A mass scale, on the other hand, does not depend on gravity, and does not need to be calibrated for location, AND it can not be use to measure the change in Gravity due to tides etc.. WarrenS _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
