Frank Nuttall at The Peak Group explores mass interconnect systems in the ­production test environment and the added benefits of advanced capabilities

Every company that builds ­complete systems or manufactures printed circuit boards does so with the intention of delivering quality, error-free products to their customers. Testing in the printed ­circuit board assembly industry is a key factor in minimising errors, and the general approach to testing is evolving in a number of ways.

Many companies employ open ­software environments in a concept called the ‘common core’ or ‘standard ­platform’ tester. In the past, companies might have built one tester for each product they intended to produce.

This approach would lead to inefficiencies as testers might fail or workloads might increase significantly, in which case one tester could not fill in for another.

With a common core tester, a ­company can build one tester with a standard platform from which all products can be tested. Besides the primary benefit of reducing complexity by requiring only one tester, this approach also creates redundancy, with any tester capable of filling in for any other tester should the same ­maintenance or workload issues arise.

Mass interconnect systems (Fig.1 Right) provide the critical connection between the tester and the unit under test (UUT). By using a receiver on the tester side and mating it with an interchangeable test adapter on the UUT side, the mass interconnect allows multiple types of I/O to be easily mated at one time, simplifying the test process and preventing many of the errors that occur with other types of connectors.

Advantages of mass interconnect systems over test systems that use custom interfaces include modularity, maintainability, upgradeability and scalability. The modularity of a mass interconnect allows for a range of contact types to be used together, whether for power, digital, RF or pneumatic signals, to name a few. The modules are selected to match the I/O of the instruments in the tester.

Hybrid modules allow mixed signal types to be used in one module, such as power and sense lines. This modular approach makes maintaining and upgrading systems extremely easy.

If a contact or the module that holds it becomes damaged, the user can easily replace the module, which keeps downtime to a minimum. Upgrading is as easy as adding additional modules to unused module slots.

Mass interconnect systems are also scalable, ranging from one to 17000 points of contact. This enables engineers to select a system that works for the products they are testing without spending money on capability they do not need.

The range of options and benefits

Options for mass interconnect ­systems, including platform support, slide kits for reduced wire length, and vertical hinged mounting frames, ­provide easy and flexible integration. These benefits are a primary reason why many companies are now choosing mass interconnects as part of their common core test strategy.

There will always be the need for a connection between the test system and the unit under test. By using a mass interconnect specifically designed for that purpose, rather than creating a custom interface, the user can ­minimise both system test time and overall cost by reducing the number of specialised testers required.

A practical implementation of these mass interconnect systems is provided by a recently introduced modular PXI test rack introduced by The Peak Group (Fig.2 Left) that provides 13U of full-depth instrumentation space and a ­further 6U of depth for rear-mounted instrumentation space.

The new system is ergonomically designed for use in production test environments, and includes an integrated VPC mass interface receiver adaptor, allowing large numbers of different contact types to be quickly and easily connected in a single operation.

This modular PXI test rack features an internal 19-inch instrument rack with slides, and is height adaptable to accept up to 42U of test instrumentation. It incorporates built-in service panels, large doors on the sides and rear and rack cooling, with a wide body allowing for cooling fans on both sides of the main chassis. It is specifically designed to fit through a ­standard single-width door.

Also incorporated are full emergency stop and door interlock safety circuitry, a mains distribution and safety circuit box, and an internal ­integrated keyboard and mouse.

The Peak Group