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70 SMT Magazine • May 2014 the type of receiver interface that the electrical system should support. Some manufacturers preferred the standard pogo-pin/bed-of-nails vacuum type fixtures, some manufacturers wanted the bed-of-nails interface with a pneumatic-type fixture. Some manufacturers wanted a press-down unit with a low-cost cassette type fixture, some wanted a simple Pylon type wire post interface that al- lowed them to wire wrap to a custom fixture interface that was compatible with an existing fixture. Based on these diverse requests, the en- gineering team designed the new brand of ICT system with a selectable receiver interface. The system can be configured with a vacuum based pogo-pin interface, non-vacuum pogo pin in- terface, wire-wrap type interface, or no inter- face at all so that it can customized by the end user to meet their specific requirements. The decision to support selectable receiver types had implications for the self-test and ac- curacy verification routines that are provided to ensure the test system is operating correctly and that the instruments are within specifications. These routines require self-test and verification fixtures designed to connect precision compo- nents on the fixtures to the tester instruments. Rather than design numerous self-test/accuracy fixtures for different receiver types, the design team decided to create a self-test module that plugs directly into the tester backplane which can be used by manufacturers and service en- gineers regardless of the selected receiver type. Simplifying Installation and maintenance The goal for the new brand of ICT system was to fit into anyone's automation equipment. The first step toward achieving that goal was to make the test system smaller. The second step was to understand the constraints of the most common automation equipment in the mar- ketplace. For this step the design team reviewed diffe- rent automation equipment designs and did a tour of Integrator/Handler equipment manufac- turers to ensure that the new ICT system would not violate any of their design constraints. The design team took care to ensure that mounting features incorporated on each of the electrical test modules would enable fast and reliable attachment to the automation equip- ment. The connections between each of the elec- trical test modules were also designed to pro- vide quick and secure attachment by incorpo- rating snap connectors, eliminating lengthy umbilical cords between modules and reducing the amount of required manual assembly steps. All of the major modules were designed for easy serviceability, accessible from the front of the system without having to perform complex di- sassembly and assembly procedures. Figure 3 shows a picture of the resulting elec- trical test subsystem ready for integration into automated handling equipment. It is designed specifically with automation in mind and has the same capabilities of the much larger system figure 3: Compact ICT subsystem designed for automation. THE CHaNGING ECoNomICS oF IN-CIRCUIT TEST continues feATuRe