The Development Of Automatic Temperature Compensation System For Piezoresistive Pressure Sensor

This research is commissioned by a nationally known company. A set ofsystem was designed in the research to make it possible to calibrate simultaneously alarge amount of piezoresistive pressure transducers by automatic temperaturecompensation. Following are the main contents of this paper:(1) The advances of the transducer self-calibration both at home and abroadwere reviewed based on a large amount of literature. At the same time, someinvestigation was made about the piezoresistive pressure transducer produced by theco-operate company, in order to understand the composition and structure of signalconditioning chip and realize the theory of the temperature compensation of thepiezoresistive pressure transducer.(2) The whole designing scheme of the automatic temperature compensationsystem was made according to the design requirement of the technical index of thecompany. The whole system was made up of four parts, which is main control unit,pressure control unit, temperature control unit, and multichannel calibration unit. Theprogram introduced the connection between the composition and structure of eachunit. Visual Basic6.0was used to develop a set of software system which can realizeautomatic control according to the systematic design requirements, improving theproduction efficiency.(3) Research of automatic temperature compensation, including pre calibrationprocess and formal compensation process. Because of MAX1452can be set up114points to compensate for temperature compensation, if all points do temperatureexperiments, the efficiency are too low. Temperature compensation in system useseveral specific temperatures, other parameters temperature compensated by threetimes spline function.(4) Through the production cycle, single station consistency verification, multistation consistency verification and batch compensation accuracyverification showsthat the system is stable and reliable. The results show sensor accuracy is in±2%,witch meet the design requirements. The introduction of machine capability index was evaluated for the system, the Cmkis more than or equal to1.67which meet thedesign requirements.