High resolution offset electronic weighing devices and methods

Abstract

Electronic weighing devices and method are disclosed wherein balances (particularly of the direct load type) are adapted to utilize less power thus creating less system heat and thereby enhancing weighing accuracy and range of operation. A preferred embodiment of the device includes a frame having an articulating load support structure connected thereto. The support structure carries a coil and movable capacitor plate while the frame locates a permanent magnet and fixed capacitor plate. An elastic offset, such as a spring, is adjustably located between the support structure and the frame to offset, or counterbalance, the support structure, preferably up to about one-half of the balance's rated capacity in any particular embodiment. A push-pull servo system initially causes current in the coil to flow in a direction producing a resultant force which is additive to the pan load. Only when the counterbalancing force is exceeded by the pan load does the coil current produce a force opposing the pan load.