Patent RU-2569924-C1 (RU)
Inventor: TIKHONENKOV VLADIMIR ANDREEVICH
IPC: G01B7/16
Filed: 2014-08-22
Granted: 2015-12-10
Abstract: FIELD: measurement equipment. 
     SUBSTANCE: sensor is connected to a load R l >500 kOhm, the initial offset is measured, as well as the output signal at normal temperature t 0 , and also temperatures t +  and t - , corresponding to the upper and lower limit of the working temperature range. The temperature coefficient of frequency of the bridge circuit          α     d   o     +           
 is calculated, and          α     d   o     −           
 at temperatures t +  and t -  accordingly, and also non-linearity of the temperature coefficient of frequency of the bridge circuit. They measure the input resistance of the bridge circuit of the sensor. The heat independent resistor is started R minp =0.5·R inp . The initial offset and the output signal of the sensor is measured at temperatures t 0 , t +  and t - . The temperature coefficient of resistance of the input resistance is calculated at temperatures t +  and t - . The resistor R minp  is disconnected. The heat-dependent process resistor R αminp , the rated value of which is more than values of the compensation heat-dependent resistor R αinp , is installed into a power supply diagonal. They measure the initial offset and the output signal at temperatures t 0 , t +  and t - . The temperature coefficient of resistance is calculated for the process heat-dependent resistor R αminp  at temperatures t +  and t - . If          α     d   o     +           
 and        Δ     α     d   o     '           
belong to the area of transformation of the positive non-linearity of the temperature coefficient of frequency of the bridge circuit into negative one, then they calculate the rated value of the resistor R αinp . The process heat-dependent resistor R αminp  is replaced with the resistor R αinp  by partial engagement of the resistor R αminp . They measure the output resistance of the bridge circuit of the sensor R outp . The sensor is connected to the low-Ohm load R l =2·R outp . The heat-dependent process resistor R αmoutp , the rated value of which is more than possible values of the compensation heat-dependent resistor R αout , is installed into the output diagonal of the bridge circuit, accordingly. At temperatures t 0 , t +  and t -  they measure values of both the initial offset and the values of the output signal of the sensor at the nominal value of the measured parameter. Into the output diagonal they connect serially with the load a heat-independent resistor R m1 =R outp , repeat measurements of initial offset and output signal of the sensor. The resistor R m1  is replaced with the resistor R m2 =2·R out , measurements of the initial offset and the output signal of the sensor are repeated. The resistor R m2  is disconnected, values of the temperature coefficient of resistance are calculated for the output resistance, the resistor, temperature coefficient of frequency of the bridge circuit after transformation of the temperature coefficient of frequency of the bridge circuit          α     d   o       '   +             
 and          α     d   o       '   −       ,         
 as well as non-linearity of the temperature coefficient of frequency of the bridge circuit        Δ     α     d   o     '     =     α     d   o       '   +       −     α     d   o       '   −       .         
 . If          α     d   o       '   +             
 and        Δ     α     d   o     '           
 belong to the area of compensation of the multiplicative temperature error with account of negative non-linearity of temperature coefficient of frequency of the bridge circuit, then the rated value of the heat-dependent resistor R αoutp  and the heat-independent resistor R ∂ are calculated. The process heat-dependent resistor R αmout  is replaced with the resistor R αoutp  by means of partial engagement of the resistor R αmoutp . The resistor R αoutp  is shunted with the heat-independent resistor R ∂ . 
     EFFECT: increased accuracy of compensation of multiplicative temperature error. 
     2 cl, 1 tbl