In road and rail vehicles, aircraft and satellites, in IT and telecommunications systems, medical equipment and industrial control systems - with all of these situations, the reliability of the electrical and electronic components is critical. As such systems grow ever more complex, the testing of these units during manufacture is becoming constantly more demanding. The use of flexible testing systems helps to cut costs in this area. A modular design of hardware also plays a significant role in achieving an optimal result. The range of types and high degree of variability and versatility then place high demands on the enclosures used for such systems.

For more than 30 years WEETECH GmbH has been a supplier of testing systems for cables, backplanes and electrical and electronic functional subassemblies. Custom solutions are developed in three different departments. Electronic testing systems perform the actual measurement or testing task and form the heart of the system. Depending on the customer's requirements these may be custom devices or configured from standard 'building blocks'. Software solutions are used for integration into the customer's manufacturing process. These range from automatic generation of the testing programme and linking in to ERP systems through to high-performance database solutions. Adaptors for the test objects and automation solutions complete the spectrum. They allow high volume testing and ensure ease of handling, marking and sorting of the tested goods. Here again the bandwidth extends from standardised modular systems through to one-off custom builds. Most of these testing systems are used in the automotive, telecommunications, aviation and space sectors, white and brown goods and in railway and military applications. For each of these areas there are product families with a common basis that can be built up or configured on a modular basis to suit the given specifications and application conditions. Individual testing systems thus result, depending on which cables, voltages and currents are to be tested and whether additional functional or high-voltage testing must be performed.

For these different testing systems WEETECH offers several alternative housing solutions. Cases for its small testing units are made in-house. Since 2002 however the company has also offered solutions based on the ratiopacPRO air series of cases. In addition to the technical requirements for cases such as robustness, ease of assembly, modular construction and EMC shielding, factors such as a straightforward ordering process, well-organised inventory control and fast implementation of custom requirements were important in deciding on Schroff and this range of cases. In this collaboration with WEETECH, Schroff GmbH has thus proved itself in recent years with its innovative products, customer proximity, straightforward communication and the implementation of new ideas, linked with an excellent price-to-performance ratio.

The ratiopacPRO air cases are used by WEETECH primarily for testing systems in aviation and space applications, military and railway systems and for high-voltage testing in the automotive sector. As a rule a testing system consists of two units, the generators and measurement systems, plus the so-called testing points. A control PC is always integrated into high-voltage testers. The configuration of the individual units depends to a great extent on the application. Where the test object is, for example, an entire train, portable units are used that weigh between 25 and 60 kg, housed in cases that are often stacked one on top of the other at various positions outside the train. These case units are linked in turn via suitable cables to the central control unit, which may itself be housed in a case or in a 19" cabinet.

As a high-end case system, ratiopacPRO is particularly suitable for demanding measurement and control applications. These cases are constructed of metal, EMC shielded and meet the requirements of the current 19" standard and the US IEEE1101.10/.11 standard. The symmetrical ratiopacPRO design enables components to be inserted from both the front (e.g. display elements) and from the rear (e.g. PSU) without the need to remove cover plates. Desktop enclosures, 19" subrack enclosures and tower versions can all be created from the same basic case. Two basic modules are available: ratiopacPRO, a space-optimised version in heights 2, 3, 4, 5 and 6 U, and ratiopacPRO air, which is 1 U higher for each of these sizes. In this design, ½ U extra space is allowed below and ½ U above the electronics, allowing cold air to be drawn in from the front and warm air to be removed from the rear. The ventilation concept, which uses either fans at the rear or radial fans in the ½ U air gap, allows these 1 U higher cases to be stacked directly one above another without loss of space or buildup of heat. WEETECH also ensures through good design that no hot spots occur in its testing systems.

The flexibility of the ratiopacPRO case is such that standard components and modified standard components can be combined in order to meet customers' special requirements cost-effectively. Custom case heights (up to 12 U) are also easy to create in ratiopacPRO. Special side panels are modified to create the requisite height, or alternatively, standard side panels are flanged together to create the height required. Particular case widths can be created by modifying the length of the horizontal rails and adapting the cover plates to suit. The case depth can likewise be altered by appropriate modifications to the side panels. Despite such alterations, however, the same components and accessories can always be used.

EMC shielding is an important aspect of testing equipment. To avoid possible corruption of the measurement data no EMC interference may enter the unit from outside. Equally, of course, the testing unit should not exert any influence on its surroundings. Measurements carried out by WEETECH have demonstrated that the metal ratiopacPRO cases fulfil these requirements with only the standard level of EMC shielding. If required, the shielding can be further increased by means of upgrade kits.

WEETECH takes advantage of the possibility of combining side panels to create larger height units. The panels are joined together with elegant and robust linking elements, which can be done with little outlay. The linking elements are later hidden behind the side panel trim and cannot be seen. A large one-piece side panel would be impractical for WEETECH, since the number of units required for a system is not determined until a firm order has been placed, and it is likewise not known whether these are to be formed of multiple height units or a standard case can be used. The modular construction options of the ratiopacPRO case series are a decisive advantage here. WEETECH therefore also stocks 'only' case kits and no pre-assembled cases. To increase suitability for stacking, steel cover plates are used rather than aluminium. Small recesses in the corners of the cover plates provide secure positioning for the rubber feet of units placed above when stacked. Optional handles or handle recesses can be fitted to the sides or on the top of the case.

WEETECH inspection systems are equipped and built differently to suit the customer's particular application. This includes front panels, which may be of various dimensions and configurations. These are individually designed and produced using Schroff's 'Front Panel Express' service. This service guarantees delivery within a time window of between 2 and 9 working days, depending on the complexity of the work required. All data required for the processing of the front panel, e.g. height, width, number of round holes, number of cut-outs, required level of EMC shielding, type of finish (colour) and choice of accessories is selected and sent by e-mail together with drawings of the panel direct to the Front Panel Express centre at Schroff. An individual quote is then prepared and the order is placed and monitored.