Electromagnetically Force-Compensating Force-Measuring Apparatus

An electromagnetically force-compensating force-measuring apparatus, comprising:

• a support coil mounted in a permanent magnet arrangement and through which a force-dependent coil current generated by a controller flows during operation as an output, and
• an integrating analog/digital (A/D) converter configured to convert an electrical signal representative of the coil current and applied to a measurement voltage input of the A/D converter, into a digital output signal,
• wherein the A/D converter is connected at the reference voltage input of the A/D converter to a reference voltage source which has two reference voltages of same magnitude and opposite polarity relative to one another, and alternately connects a reference voltage switch to an integrator of the A/D converter, wherein a ratio of intervals in which the reference voltages are respectively connected to the integrator within a measuring clock cycle provides a measure of the coil current presently flowing,
• and wherein the output of the e controller is connected, via an inverter, a first heating resistor which is thermally coupled to the support coil, and a second heating resistor to an output of a voltage amplifier, the input of which amplifier is connected to an output of the reference voltage switch, wherein a passive current/voltage converter with a shunt resistor connected to wound is connected downstream of the support coil, an output of the current/voltage converter being connected to the measurement voltage input of the A/D converter, wherein
• a resistance value of the first heating resistor is equal to a resistance value of the support coil,
• a resistance value of the second heating resistor is equal to a resistance value of the shunt resistor, and
• a gain factor of the voltage amplifier is equal to a ratio of a total of the resistance values of the first and second heating resistors to the resistance value of the second heating resistor (RWH).