In-Circuit Test Systems-An Evolution

This paper surveys the development of in-circuit testing over the past decade and examines the reasons as to why this production floor technique for test and fault diagnosing of printed wiring assemblies has taken hold. Both controller based and minicomputer based in-circuit test systems are discussed, and reasons are advanced as to why minicomputer based in-circuit systems are becoming popular. Some of the reasons presented are their ability to employ the simple programming languages such as Basic. Moreover, users may readily add functional testing to a minicomputer based in-circuit test system by interfacing some of the programmable instruments now on the market with the input-output bus and the in-circuit test fixture. It is also pointed out that minicomputer based in-circuit test systems provide the capability to generate in-circuit test Programs by an operator, unschooled in minicomputer programming, who merely enters data from engineering documents. A test program generator generates the tests in the proper testing sequence. The paper Concludes with a discussion as to how in-circuit and functional testing can be combined effectively for optimizing test and fault diagnostic capability.