| 摘要 |
FIELD: electricity.SUBSTANCE: gauge is connected to high-resistance load R>500kOhm, initial unbalance and output signal of the gauge is measured at temperature t, as well as temperatures tand tcorresponding to the upper and lower limit of the operating temperature range. Temperature coefficient of frequency is calculated for bridge measuring circuitandat temperatures tand trespectively as well as non-linearity of temperature coefficient of frequency for the bridge measuring circuitInput resistance is measured for bridge circuit of the gauge. Thermally independent process resistor R=0.5·Ris switched on. Initial unbalance and output signal of the gauge is measured at temperature t, tand t. Temperature coefficient of frequency is calculated for input resistance at temperature of tand t. Resistor Ris switched off. Thermally independent process resistor R, which rate value is more than permissible values of compensatory thermally dependent resistor R, is mounted to power supply diagonal of the bridge circuit. Initial unbalance and output signal of the gauge is measured at temperature t, tand t. Temperature coefficient of frequency is calculated for process thermally dependent resistor Rat temperature tand t. When temperature coefficient of frequency (TCF) of the bridge circuit and its non-linearity belong to the area of TCF positive non-linearity of the bridge circuit to negative one, then rate value of thermally independent resistor Ris accepted as 0.1·R, rate values of resistors Rand Rare calculated. Process thermally dependent resistor Ris replaced by resistor Rby partial involvement of resistor R. Input resistance of the bridge circuit is shunted with resistors Rand Rintercoupled in series. Resistor R=0.1·Ris switched on to power supply diagonal of the bridge circuit. Output resistance Ris measured for bridge circuit of the gauge. The gauge is coupled to low-resistance load R=2·R. Initial unbalance and output signal of the gauge is measured at temperature t, tand t. Measurements are repeated upon shunting of output resistance of the bridge circuit by thermally independent resistors R=R. TCF of the bridge circuit is calculated upon conversion of TCF non-linearity of the bridge circuitandtemperature resistance coefficient (TRC) is measured for the bridge circuit at temperature of tand trespectively as well TCF non-linearity of the bridge circuitThermally dependent process resistor, which rate value is more than permissible values of compensatory thermally dependent resistor R, is mounted to power supply diagonal of the bridge circuit. Initial unbalance and output signal of the gauge is measured at temperature t, tand t. TCF is calculated for process thermally dependent resistor Rat temperature tand t. Ifandbelong to the compensatory area of multiplicative temperature error considering negative TCF non-linearity of the bridge circuit, then rate value is calculated for thermally dependent resistor Rand thermally independent resistor R. Process thermally dependent resistor Ris replaced by resistor Rby partial involvement of resistor R. Resistor Ris shunted by thermally independent resistor R.EFFECT: higher accuracy of compensation.2 cl, 1 tbl |
