PRESSURE CONVERTER Russian patent published in 1995 - IPC

FIELD: instrumentation engineering. SUBSTANCE: power supply source with positive feedback by voltage across strain-measuring bridge 1 is used for compensation of errors. Circuit of converter has instrumentation strain-measuring bridge 1, reference resistor 8, voltage divider 3, controlled voltage source 5 connected to input of divider 3 and to diagonal of power supply of strain-measuring bridge through reference resistor 8. Circuit is supplemented with differential amplifier 4, voltage amplifier 7 for power supply of strain-measuring bridge, voltage amplifier 2 of unbalance of strain-measuring bridge and subtracter 6. Inputs of amplifier 4 are linked to output of divider 3 and to diagonal of strain- measuring bridge. Output of amplifier 4 is connected to input of voltage source 5 manufactured in the form of adder. Gain factor of amplifier 4 is equal to , where GFSG and TCR are correspondingly temperature coefficients of strain sensitivity and resistance of strain-measuring bridge. Drift of initial unbalance of strain-measuring bridge 1 is compensated with the help of subtracter 6 connected with inputs correspondingly to outputs of amplifiers 2 and 7. Amplifier 7 is coupled with input to diagonal of strain-measuring bridge 1 and has gain factor equal to ratio of voltage across output of amplifier 2 to voltage across input of strain-measuring bridge. EFFECT: improved capability for simultaneous compensation both multiplicative and additive errors. 1 dwg