摘要:
In order to compensate for the effects of temperature variations on a transducer such as a piezo-resistive bridge (1), the bridge is fed from a temperature dependent power supply circuit (6-17). The power supply circuit comprises a temperature sensitive element (11) with first and second adjustment means (16, 15) for adjusting the slope of supply voltage for the transducer against temperature on first and second sides, respectively, of a predetermined temperature. The second adjustment means (15) provides an adjustment which is independent of the first adjustment means so that repeated temperature cycling during calibration is unnecessary.
摘要:
A differential pressure sensor (10) senses a difference in pressure between a first input (low) pressure (12) or "reference pressure" and a second input (high) pressure (14) and provides a differential sensor signal representative of the difference in pressure. The reference pressure is sensed by a reference pressure sensor (26) which provides a reference signal representative of the reference pressure. The differential sensor signal and the reference signal are provided to a correction circuit. The correction circuit (24), which is preferably a digital computer, adjusts the reference signal and provides an improved output signal as a function of the differential sensor signal and the adjusted reference signal.
摘要:
A temperature compensated pressure sensor system for well logging includes optically activated and interrogated pressure and temperature transducers (12). The transducer outputs are transmitted in a modulation of an optical carrier to a remote station (11).
摘要:
The temperature coefficient of the combination of a transducer (T) and any one of a plurality of disposable plastic domes (D) manufactured to given specifications is reduced substantially to zero by making the temperature coefficient of the transducer (T) when the pressure dome (D) is not mounted therto equal in magnitude and opposite in sign to the change in temperature coefficient that results from mounting the average dome (D) to the transducer (T). The temperature coefficient of the transducer (T) is permanently adjusted by laser trimming a temperature-dependent resister (R x , R T ) of a bridge circuit (R A . R B , R C , R V , R T , R x . Ry) coupled to be imbalanced by variations in a pressure sensitive impedance (Z) of the transducer (T).
摘要:
A differential pressure unit to induce tension and compression in respective strain gages to produce a change in the output of a Wheatstone bridge. The differential pressure or some function thereof is then indicated. Error due to temperature is avoided by maintaining the bridge current constant The bridge voltage is elevated as a function of temperature to make the bridge current or bridge output independent of temperature.
摘要:
Amplifier circuit for temperature compensating the output voltage thereof with respect to undesirable temperature induced signals from a silicon pressure transducer (10) and/or from components of the amplifier itself. The amplifier includes a first operational amplifier (50) and a second operational amplifier (68). A first circuit connects the output terminal of the first operational amplifier through a summing node (66) to one input terminal (70) of the second amplifier. Output signals from the pressure transducer are applied between one input terminal (52) of the first operational amplifier and another input terminal (72) of the second amplifier. A temperature compensating circuit (116) is connected to the summing node for enabling the output voltage of the amplifier to be substantially independent of temperature. An initial offset voltage compensating circuit (80) is coupled to the summing node for adjusting the intercept of the pressure-to-output voltage transfer curve. The gain of the second operational amplifier determines the slope of the curve.
摘要:
A differential pressure unit to induce tension and compression in respective strain gages to produce a change in the output of a Wheatstone bridge. The differential pressure or some function thereof is then indicated. Error due to temperature is avoided by maintaining the bridge current constant The bridge voltage is elevated as a function of temperature to make the bridge current or bridge output independent of temperature.