Enclosure technology is not necessarily one of the core competencies of companies that offer electronic assemblies for industrial applications. To enable them to concentrate on the development and marketing of their products, they often source the enclosures from external suppliers.
Some of the basic requirements for the enclosures are that they must comply with market and application-relevant standards and that they can be mounted easily and without tools by snapping them onto the DIN mounting rail. Connections on the front of the enclosure ensure that the modules can be wired in a time-optimized manner thanks to the easy accessibility of the terminal points. Another requirement is that the enclosures can be arranged as individually as possible and adapted to the application in order to reflect the manufacturer's corporate design. The example of the 'KV' series enclosure systems from Dold shows how such individualization can be achieved. These enclosures in widths of 12.5 mm, 17.5 mm and 22.5 mm can also be customized cost-effectively for small to medium batch sizes.

On the front of the housing

Automation, measurement and safety technology are typical applications in which assemblies are housed in modules in the control cabinet. Due to increasing digitalization, the number of inputs and outputs and the number of additional interfaces for possible fieldbus connections are increasing in most applications.
Large front surfaces, such as in the 'KV' enclosures, allow individual arrangement of connection terminals and the integration of common connections such as RJ45, USB or Sub-D. It is also possible to install displays or LED strips to signal functional statuses. NFC, radio or fiber optics can also be implemented. Sealable, hinged front covers help to prevent unauthorized tampering with the devices. If all connections are located on the front of the device, space-saving installation in the control cabinet is possible. In addition, wiring and connecting the modules is simple and time-saving. Push-in terminals with a 3.5 mm or 5 mm pitch, which can be processed using reflow soldering technology, are provided for wiring the KV housing. They have a test tap, which can be used to carry out a quick diagnosis in the application. The usable area of the PCBs is over 9,500 mm2. Two PCBs can also be accommodated in the wider housings.

Flexible concept for individualization

The DIN rail bus system ensures both simplified communication and the power supply for the individual modules.

© Dold

The enclosures are injection molded from polycarbonate and meet all application-specific requirements of the relevant automation, measurement and safety technology standards. Thanks to the self-extinguishing material of the enclosures, the UL fire protection requirements are also no problem - the enclosures meet the V0 classification in accordance with UL94. Their design with labyrinthine geometries enables compliance with the clearance and creepage distances of 8 mm required by the standards to maintain immunity to static electricity discharge. At the same time, the space on the PCB can be optimally utilized for the placement of electronic components. The housings are optimally designed and consist of only two main housing components. They can be assembled without tools - once the PCB has been installed, the individual parts are simply clipped together. Lateral ventilation slots ensure heat dissipation through free convection. The degree of protection is at least IP20; IP30 or IP40 are also possible without ventilation slots and cut-outs in the front of the housing.

Every application is different and requires, for example, a different number of terminals or different interfaces. Accordingly, different cut-outs in the front surface are necessary. Dold has developed a flexible system to enable individualization of the enclosures even for small batch sizes, so that individualization can also be implemented cost-effectively for batch sizes from around 250 units per year.
Another option for individualization is marking the housing surfaces. Dold has systems for laser, pad or digital printing available for this purpose.
This allows the devices to be provided with logos, type and connection designations, etc. In digital printing, the enclosures can also be printed in full color and thus adapted to the manufacturer's corporate design, for example.

Enclosures in the Industry 4.0 era

The fronts of the 'KV' enclosures can be customized and thus adapted to the requirements. The push-in terminals used have a test tap for quick diagnosis.

© Dold

Networking and communication in the field of industrial and building automation are becoming increasingly important. For electronic modules in the control cabinet, this often means that a bus connection must be provided between different modules. Dold uses a so-called DIN rail bus system for this purpose, which is available as a five or eight-pole version. It is snapped into the DIN mounting rail and provides cables for power supply and signals. The individual modules are connected to the bus via a contact spring block. This eliminates the need for time-consuming individual wiring of the modules. Users can then implement bus protocols such as CAN bus, Modbus, RS232 or RS485 via the DIN rail bus system. As an alternative to this solution, an individual module for a bus system is possible in the area of the base module of the housing.

This article was based on a design by E. Dold & Söhne in Furtwangen.