REFINEMENTS FOR EDDY CURRENT TECHNIQUES

EDDY CURRENT FIELD INSPECTIONS ARE PRESENTLY PERFORMED BY TECHNICIANS WHO MUST EXAMINE AND EVALUATE THE OUTPUT OF EDDYCURRENT EQUIPMENT AND MANUALLY RECORD THE RESULTS OF SUCH INSPECTIONS. AN INVESTIGATION INTO THE FEASIBILITY OF IMPLEMENTING A DIGITAL SYSTEM WHICH AUTOMATES THIS PROCESSS IS THE OBJECTIVE OF THIS STUDY. THE SYSTEM IS BASED UPON A GENERAL PURPOSE, LOW-COST PERSONAL COMPUTER. IT AUTOMATICALLY PERFORMS AND RECORDS EVALUATIONS OF THE ANALOGOUTPUT OF EDDY CURRENT INSTRUMENT, BASED ON CRITERIA CURRENTLY USED FOR ANALOG OUTPUT EVALUATION. THE SYSTEM REQUIRES SPECIAL-PURPOSE SOFTWARE AND ANALOG-TO-DIGITAL CONVERTERS; THE LATTER IS BUILT USING LOW-COST, OFF-THE- SHELF, MODULAR COMPONENTS. BY LIMITING SYSTEM MEMORY CAPACITY (AND ASSOCIATED COST), A SYSTEM DESIGN IS DEVELOPED WHICH WOULD ALLOW FOR A DELAY OF SEVERAL SECONDS BETWEEN EDDY CURRENT DATA ACQUISITION AND ITS EVALUATION BY THE SYSTEM. THIS PROVIDES IN-SERVICE EDDY CURRENT FIELD INSPECTIONS WITH A CAPABILITY THAT IS NOW POSSESSED BY MANY FIXED, IN-PLANT FABRICATION FACILITIES.