Provided is an electronic balance of electromagnetic force type including a weight automatic loading mechanism which can place and remove a weight by its own mechanism without use of either an external balance weight or a built-in balance weight. An electronic balance of electromagnetic force type is provided with a beam equilibrium setting unit that sets two or more equilibrium states of the beam position detecting unit. By making conversion ratios of upper and lower light receiving circuits nonequivalent, an imaginary weight is generated by utilizing the operating principle of the electromagnetic balance of electromagnetic force type.

An electromagnetically force-compensating force-measuring apparatus (100) that includes a force dependent support coil (2) and an integrating analog/digital converter (10; 10) that converts the coil current (I.sub.S) into a digital output signal. A current/voltage converter (6) is connected downstream of the support coil (2), the output of the current/voltage converter being connected to a measurement voltage input (14) of the analog/digital converter (10; 10) and to the input of a voltage amplifier (8). The resistance value of a first heating resistor (R.sub.SH) is equal to the resistance value of the support coil (2), the resistance value of a second heating resistor (R.sub.WH) is equal to the conversion factor (R.sub.W) of the current/voltage converter (6) and the gain factor of a voltage amplifier (8) is equal to the ratio of the resistance value of the first heating resistor to the resistance value of the second heating resistor.

An electromagnetically force-compensating force-measuring apparatus (100) that includes a force dependent support coil (2) and an integrating analog/digital converter (10; 10) that converts the coil current (I.sub.S) into a digital output signal. A current/voltage converter (6) is connected downstream of the support coil (2), the output of the current/voltage converter being connected to a measurement voltage input (14) of the analog/digital converter (10; 10) and to the input of a voltage amplifier (8). The resistance value of a first heating resistor (R.sub.SH) is equal to the resistance value of the support coil (2), the resistance value of a second heating resistor (R.sub.WH) is equal to the conversion factor (R.sub.W) of the current/voltage converter (6) and the gain factor of a voltage amplifier (8) is equal to the ratio of the resistance value of the first heating resistor to the resistance value of the second heating resistor.

A balance (1) has a weighing pan (3) that is held in a predetermined free-floating and constant position relative to translatory and rotary displacements in the six degrees of freedom during use. At least six position sensors are used to measure the position of the weighing pan in all three dimensions. A weighing mechanism having at least six electromagnetic mechanisms (5) generate compensation forces (F.sub.c1-F.sub.c6) that act on the weighing pan by sending currents through a force coil (7) associated with an associated permanent magnet. The weight of an object on the weighing pan is determined from the amounts of current flowing in the respective force coils to maintain the weighing pan in position.

A system includes a platen assembly having a platen and a magnet coupled with an underside of the platen. The system also includes a base assembly having a storage component and a base magnet coupled with the storage component. The base magnet and the magnet of the platen are magnetically coupled to secure the platen in place relative to the base assembly. The system also includes an electromagnet that is selectively activated to increase a holding strength of the platen to the base assembly. Techniques for selectively activating an electromagnet to increase a holding strength of a platen to a base assembly are also provided.

A system includes a platen assembly having a platen and a magnet coupled with an underside of the platen. The system also includes a base assembly having a storage component and a base magnet coupled with the storage component. The base magnet and the magnet of the platen are magnetically coupled to secure the platen in place relative to the base assembly. The system also includes an electromagnet that is selectively activated to increase a holding strength of the platen to the base assembly. Techniques for selectively activating an electromagnet to increase a holding strength of a platen to a base assembly are also provided.

A system includes a platen assembly having a platen and a magnet coupled with an underside of the platen. The system also includes a base assembly having a storage component and a base magnet coupled with the storage component. The base magnet and the magnet of the platen are magnetically coupled to secure the platen in place relative to the base assembly. The system also includes an electromagnet that is selectively activated to increase a holding strength of the platen to the base assembly. Techniques for selectively activating an electromagnet to increase a holding strength of a platen to a base assembly are also provided.

A system includes a platen assembly having a platen and a magnet coupled with an underside of the platen. The system also includes a base assembly having a storage component and a base magnet coupled with the storage component. The base magnet and the magnet of the platen are magnetically coupled to secure the platen in place relative to the base assembly. The system also includes an electromagnet that is selectively activated to increase a holding strength of the platen to the base assembly. Techniques for selectively activating an electromagnet to increase a holding strength of a platen to a base assembly are also provided.

A force measuring device based on the principle of electromagnetic force-compensation is disclosed. The device includes an electronic circuit driven by direct current, which includes an inductor. A control unit of the device controls the current flowing through the inductor and thereby also the compensation force, where the controlling is responsive to the force to be measured. The device also includes a means for providing a measurement output indicative of the force to be measured. Controlling the current includes dynamic switching between two switch states associated with the two conduction directions of the inductor.

The disclosure relates to a scale operating according to the principle of electrodynamic force compensation and to a method for its operation. An automatic switchover from a measuring mode to an overload mode is provided for detecting overload forces. In this overload mode the load resistance formed by a coil and at least one measuring resistor is reduced in order to allow a higher coil current at the same output stage power.