How does the Super Hybrid Sensor (SHS) work?

The basic principle of the GX device is force restoration motor.  Any change in the load on the weighing pan causes a position beam lever to pivot on two fulcrum flexures (refer to diagram below).  Attached to this beam is a bobbin (wound with fine wire), called the "force coil."  This bobbin floats in a permanent magnet called the force motor.  At the end of the position beam lever, there is a small hole which allows light from a light-emitting diode (LED) to pass through to two photodiodes (light measuring diodes) as it moves up or down.  At zero weight, the light detected by the upper photodiode is equal to that detected by the lower photodiode.  These three diodes make up the position detector.

When the force coil is pulled up by the leverage exerted from a mass on the weighing pan, the position detector detects a change in the position of the force coil as the light reaching the upper photodiode will be greater than that reaching the lower one.  The balance then feeds the force coil with more voltage to pull it back until the light measured by the two photodiodes is equal, and the mechanism is once again balanced.  This is accomplish by the analog module receiving photocurrent from the photodiodes, converting it to voltage and sending it back to the force coil.  As the voltage increases, so does the magnetic power pulling the force coil back until the position detector reads equilibrium (balance).

The current flowing through the force coil generates a voltage proportional to the load weight on the pan.  This is read back through the analog module, first being filtered -- then the analog to digital converter digitizes this measuring voltage, the resulting value is counted and then fed to the microprocessor.

Temperature affects the magnet and weight data.  So temperature coefficient for weight is measured and saved beforehand.  The balance eliminates the temperature effect by using the present temperature measured by the temperature sensor and the coefficient.  The output from the temperature sensor is converted digitally and sent to the CPU by the analog module.

The CPU performs a mathematical operation in connection with each parameter, such as temperature, linearity coefficient, and calibration data.  Also, the user can specify how the calculated information should be displayed by using the keyboard.  For example:  they can have the CPU perform special functions such as conversion into other measuring units or counting of small parts.  Finally, the results are displayed on the fluorescent display, or sent through the RS-232C interface.

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