METHOD TO ADJUST RESISTANCE STRAIN GAUGE SENSORS WITH BRIDGE MEASUREMENT CIRCUIT USING MULTIPLICATIVE TEMPERATURE ERROR WITH ACCOUNT OF POSITIVE NON-LINEARITY OF TEMPERATURE CHARACTERISTIC OF SENSOR OUTPUT SIGNAL Russian patent published in 2014 - IPC G01B7/16 

FIELD: measurement equipment.

SUBSTANCE: invention relates to measurement equipment and may be used to tune resistance strain gauge sensors with a bridge measurement circuit according to multiplicative temperature error. Substance: at load resistance R_l≥500 kOhm they determine temperature sensitivity coefficient (TSC) of the bridge circuit $${\alpha }_{do}^{+}$$ and $${\alpha }_{do}^{-}$$ at temperatures t⁺ and t^-, which correspond to the upper and lower limit of the working range of temperatures, and non-linearity of the TSC of the bridge circuit $$\left(\Delta {\alpha }_{do}={\alpha }_{do}^{+}-{\alpha }_{do}^{-}\right).$$ If the produced value ∆α_do is positive, then positive non-linearity of the bridge circuit TSC is converted into negative one. For this purpose they determine input resistance and its temperature resistance coefficient (TRC), as well as TSC of resistance strain gauges $${\alpha }_d^{+}$$ and $${\alpha }_d^{-}$$ at temperatures t⁺ and t^- and calculate non-linearity of TSC of resistance strain gauges $$\left(\Delta {\alpha }_d={\alpha }_d^{+}-{\alpha }_d^{-}\right).$$ The rating of the thermally dependent resistor R_αinp, and the rating of thermally independent resistors R_dinp, and R_i are calculated. The resistor R_i is installed into the power supply diagonal of the bridge circuit, the input resistance of which is shunted by serially connected resistors R_αinp and R_dinp. The TSC of the bridge circuit is determined under temperatures t⁺ and t^-, the non-linearity of TSC of the bridge circuit is calculated as ∆α_do. If non-linearity of the TSC takes a negative value that meets the inequality ∆α_do≤-2·10^-6 1/°C, then multiplicative temperature error is compensated for by means of calculation and connection of a thermally dependent resistor R_αout, shunted with a thermally independent resistor R_dout, into the output diagonal of the bridge circuit in series with the load.

EFFECT: increased accuracy of tuning with positive non-linearity of bridge circuit TSC.

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