INDIRECT METHOD OF ADJUSTMENT OF STRAIN SENSORS WITH BRIDGE MEASURING CIRCUIT AS PER MULTIPLICATIVE TEMPERATURE ERROR CONSIDERING NEGATIVE NON-LINEARITY OF TEMPERATURE CHARACTERISTIC OF OUTPUT SENSOR SIGNAL Russian patent published in 2015 - IPC G01B7/16 

FIELD: measurement equipment.

SUBSTANCE: invention relates to measurement equipment. Essence of the invention is as follows: temperature-dependent technological resistor R_αm, the nominal value of which is higher than possible values of compensation temperature-dependent resistor R_α, is installed into an output diagonal of the bridge circuit. A bridge is installed parallel to resistor R_αm. Output resistance of bridge circuit R_out is measured. The sensor is connected to low-resistance load R_l=2·R_out. Initial imbalance and an output signal of the sensor is measured at normal temperature t₀, as well as at temperature t⁺ corresponding to an upper limit of the working temperature range, and t^- corresponding to a lower limit of the working temperature range. Measurements are repeated after the sensor is connected to low-resistance load $$R_I^{\text{'}}=R_{out}.$$ Based on the measured values of the initial imbalance and the output signal of the sensor there calculated is temperature coefficient of frequency (TCF) of the bridge circuit $${\alpha }_{s\text{ meas}}^{+},$$ and $${\alpha }_{s\text{ meas}}^{-}$$ and TCF of output resistance at temperatures t⁺ and t^- respectively, as well as non-linearity of TCF of the bridge circuit ( $$\Delta {\alpha }_{s\text{ meas}}={\alpha }_{s\text{ meas}}^{+}-{\alpha }_{s\text{ meas}}^{-}$$ ). The bridge is removed from resistor R_αm. The initial imbalance and the output signal of the sensor is measured at temperatures t₀, t⁺ and t^-. Based on the measured values of the initial imbalance and the output signal of the sensor, TCF of temperature-dependent resistor R_αm is calculated at temperatures t⁺ and t^-. If TCF of the bridge circuit and its non-linearity belong to the application field of the method, then, the nominal value of temperature-dependent resistor R_α and temperature-nondependent resistor R_∂ is calculated. Process temperature-dependent resistor R_αm is replaced with resistor R_α by partial activation of resistor R_αm. Resistor R_α is shunted with temperature-nondependent resistor R_∂.

EFFECT: higher compensation accuracy.

2 cl