The Design And Realization Of Intelligent Digital Calibrator Of Pressure

Pressure is parameter of pyrology, play important rolesin industry scene and research work. Pressure measure isdeterminant factor at ensuring product quality andproduction safe in enterprise. Pressure transducers andpressure meter have been used in manufactory. So it isconcerned if these pressure meters are correct. But theusual equipments of measurement are very inefficient. Thesefactors direct affect convenient and exact measuringpressure.The carry-home intelligent digital calibrator ofpressure includes intelligence techniques and integrationtechniques. The calibrator is made up of two parts byfunction. The first part is pressure module ofcalibrator .It is composed of managing power circuitry,sampling signal circuitry, temperature calibrationcircuitry of pressure signal and control circuitry. Achievesampling pressure signal, linearity correct of pressuredisplay value, communication with host. The transmissionsignal is anti-jamming, because signal level is TTL level.Raise transmission quality. To measure pressure is reliableand carry-home in scene, because intelligent pressuremodule is manufactured. The second part is host ofcalibrator .It is composed of power managing circuitry,communication circuitry, measuring circuitry ofelectricity and output circuitry of DC24V. Calibrator candistinguish intelligent pressure modules, manage charge anddischarge of battery, accurately measure signal output ofmeter. Measure pressure is convenient. The A/D converter AD7710 is 24 bits IC according Σ-Δ charge balance technique that is produced by AD corp.Adopt the high precision A/D converter AD7710 in the designof intelligent pressure module. Considering output signalof the pressure sensor drift, therefore adopt high precisionVtemperature transducer AD590 that is produced by AD corp.Adopt temperature modulus 1μA/K of AD590 and sencond inputchannel of AD7710,successfully achieve automatictemperature calibration for pressure signal, improvepressure measure precision .The power manage circuitry inthe pressure module ensure high sampling precision ofAD7710.In the software, achieve pressure valuemulti-calibration using intercalary value theory, displayvalue is close to fact value still. The transmission signalis the more less the more better in the link of pressuremodule and host for ensuring dependable communication.Synthetically consider, adopt cable transmission line with6 cores and shield .The old pressure calibrator can'tanti-jamming, because transmit weak analog electricalsignal. Whereas, in the design, the amplitude oftransmission electrical signal is high, anti-jamming.In the host design, adopt encoder 74HC139,successfullyachieve communication with pressure module and computer. Inaddition at this rate don't increase load of program. Themulti-instrument communication of principal andsubordinate is achieved by agreement before. In the design,it is achieved by circuitry, thus decrease complicatedjudgment in the program and communication mistake. Alsoadopt the high precision A/D converter AD7710 in the designof host. Accurately measure output of inspected meter undercontrol of microcomputer 89C52.Adopt charging Ni-H batteryand AC Adapter for expediently measuring pressure. Adoptcircuitry for rational using both. Has indication whenelectrical voltage of battery is low. The calibrator high-efficiency works dependent on the reasonable managingcircuitry of power. In addition in the host increase outputof DC24V for calibrating transducer of pressure.According to calibration rules of all kinds ofinspected meters, the computer software compilescalibration certificate. The intelligent digitalcalibrator of pressure is measuring calibrator. In themeasuring process, successively write or automaticallysample value of inspected meters, accomplish printing andsaving of certificate.Technical target of the intelligent digital calibratorof pressure: the measuring accuracy of pressure is(±0.05%F.S),The measuring accuracy of electricity is ±(0.02%R.D+0.003%F.S);A host can select load of pressuremodule,measuring accuracy of pressure only is dependenton pressure module, is independent of host。...