The Development Of Automatic Calibration System For Digital Multimeter

DMM is a test-equipment most commonly used in modern industrial,electrical and electronic measuring,is one of the widely used standard equipment calibration laboratory.It’s indication of the accuracy direct impact on product quality.DMM regularly test calibration has a very important significance.In order to solve the problem of DMM calibration which is repeated and complex operations and calculations manual operation,to avoid human error and improve test efficiency,the author choose DMM automatic calibration software development as the research subject.On one hand it can make our own work to further improve efficiency,on the other hand it also can fill the blank of our Institute of Metrology in DMM automatic calibration.The author primarily based on the national DMM verification regulation to determine the projects of the automated calibration test.The author selects FLUKE 5720 Multifunctional standard source Calibrator and 8846A series DMM as the hardware foundation.Then,use Visual Basic 6.0 language to achieve computer program control,USB-GPIB port as the system hardware technical proposal and NI VISA as the system software technical proposal.Then the calibrator calibrates the DMM in AC and DC voltage,DC current,Resistance and the measured data is sequentially written into the form template,at the same time to calculate error values so that the user can judge whether or not qualified.At the end of the calibration,it can automatically generate WORD certificate so that it can be called,saved and printed.The calibration system achieved the DMM’s automatic calibration,easy to operate,convenient to use,and high accuracy.A great many DMM are calibrated through the automatic calibration system,the result indications the system running stable and reliable,increasing measurement capacity,which achieves the desired research purpose.