Modular electronic housings

CAD models and customer-specific part numbers minimise the effort required for design-in, production and stock-keeping. Maximum freedom in the design of the connection concept, as well as components that can be customised with both cutouts and printing, complete the offering. As an example, this article describes the simple design-in of electronics for overspeed protection into the housing using engineering data.

Istec International, a company based in the Netherlands, specialises in condition monitoring and overspeed protection of rotating machinery. SpeedSys is an example that focusses on SIL2 or SIL3 overspeed protection for compressors, pumps, aeroderivative gas and steam turbines and marine applications. Depending on the area of application, the connected sensor technology is located in the potentially explosive zones 0, 1 and 2. Accordingly, the input circuitry of the device is intrinsically safe ATEX/IECEx approved. Competing (legacy) products on the market are predominantly designed for mounting in a 19-inch rack; a proven solution, but one that no longer meets the requirements of the modern day and age of lightweight and compact systems and is slowly being phased out.

Istec wanted to place a universal, compact measurement and monitoring unit on the market, which on the one hand can be universally integrated into new applications but is also well suited for retrofitting. The sensors already in the system should be able to continue to be used by means of configurable inputs and outputs. All electronics are accommodated in a compact housing that can be mounted on a DIN rail in a control cabinet or integrated in a subrack in an existing 19” rack for retrofit applications.

Form meets function

Istec did not want just any housing, but a highly functional modular system whose design would set it apart from the standard solutions in the control cabinet - an eye-catcher that would emphasise the high-quality technology. The choice fell on Weidmüller's modular, IP20-protected CH20M45 and CH20M67 electronic housings, which were customised. A key advantage of these housings is the free choice of connection levels; even an asymmetrical configuration is possible. This allows the devices to be replaced without the need for rewiring. With up to 18 socket connectors providing 72 connection points overall, the wide CH20M67 housing offers a high level of freedom in the design of circuit board.

A further benefit of Weidmüller’s socket connectors is the option around coding, allowing devices to be replaced without rewiring fault-free. Another criterion is the ATEX/IECEx approval. Under no circumstances may impermissible voltages be conducted into the Ex-protected areas due to a connection error. Therefore, the connections must be clearly marked. Weidmüller provides coded socket connectors with blue release levers for this purpose. These helps identify all field connections, minimising the risk of incorrect wiring.

Designing electronics into an enclosure is a time-consuming and labor-intensive process. In this development phase, Weidmüller was able to support Istec as a competent enclosure supplier. First, the Weidmüller Configurator WMC was used to create initial visualisations of the enclosure. PCB contours as well as CAD data of the enclosure are basic requirements for working in the company's own engineering system and were provided by Weidmüller. This meant that Istec had all the development-relevant information in the desired form and was able to define the cutouts for the front element in its own CAD system, enabling Weidmüller to produce the initial sample series of housings for Istec. These housings also served as release samples.

Once development is complete, each customised component is given its own part number. This enables Istec, for example, to order a bespoke front element with cutouts for status LEDs and service interfaces just as easily as a standard terminal block. This allows the device manufacturer to concentrate fully on its core business.

With Weidmüller's high-quality components and services, Istec can now place first-class devices on the market that make a real statement in the control cabinet with their striking design and excellent technology.

Istec is convinced by the housing and the services and will continue to rely on Weidmüller housings for further developments, such as the RecipSys 200.

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