FIELD: measurement equipment.
SUBSTANCE: at load resistance RL≥500 kOhm they determine a temperature sensitivity coefficient (TSC) of a bridge circuit α+ do and α- do at temperature t+ and t-, corresponding to upper and lower limit of the working temperature range, and non-linearity of bridge circuit TSC (Δαdo=α+ do-α- do). If the produced value Δαdo is positive, they convert the positive non-linearity of the bridge circuit TSC into the negative one by inclusion of a heat-independent resistor Ri into a diagonal of power supply and simultaneous shunting of inlet resistance with a heat independent shunt, which is formed by serial inclusion of a heat-independent resistor Rαinp and a heat-independent resistor Rdinp. For this purpose they determine input resistance and TSC of input resistance, and also TSC of resistance strain gauges α+ d and α- d at temperature t+ and t-, and they calculate non-linearity of bridge circuit TSC (Δαd=α+ d-α- d). If α+ d and Δα- d are in the field of conversion of positive non-linearity of bridge circuit TSC into the negative, then they take the nominal value of the heat independent shunt equal to input resistance, and the nominal value of the resistor Ri. as equal to 100 Ohm. They calculate nominal values of resistors Rαinp and Rdinp. They connect resistors Ri, Rαinp and Rdinp into the diagonal of bridge circuit power supply. The TCS of the bridge circuit is defined at the temperature t+ and t-, non-linearity of the bridge circuit TCS is calculated as Δαdo. If Δαdo takes the negative value, then compensation of multiplicative temperature error is carried out with account of negative non-linearity of bridge circuit TSC by inclusion of a heat independent resistor Rαoutp, shunted with a heat independent resistor Rdoutp, into the output diagonal of the bridge circuit under the resistance of the load RL≤2 kOm.
EFFECT: higher accuracy of compensation.
2 tbl, 2 dwg
