Cables/Connecting

Everyone’s an individual

7th August 2013
Nat Bowers

How a new approach to the single-strand wiring of PCBs addresses existing challenges by offering a powerful, reliable, economical and easily installable interconnection solution. Kevin Canham, Production and Application Manager with Harting Technology Group, explores more in this article from ES Design magazine.

The trend towards the miniaturisation of the electronic circuitry used in industrial systems means that more functions are being combined in single devices or applications. At the same time, individual devices are becoming more flexible to fulfil different functions such as memory, measurement and control, both centrally and peripherally. Powerful miniature devices require powerful termination concepts that can also be implemented economically.

In the future, industrial systems, machines and instrumentation will continue the trend towards further miniaturisation. As a result, more and more functions will have to be combined in one device or one application. Application software will take on additional functions and will become increasingly powerful. At the same time, individual devices will become smaller and smaller, with no significant reductions in performance and reliability.

A not insignificant reason for these trends involves the implementation of electronic control elements that make the devices more flexible and their use more precise. Devices that started off as specialised or ‘insular’ systems are now becoming suitable for broader use. At the same time, they can be implemented in complex systems where they fulfil different functions as memory, measurement or control devices, both centrally and peripherally. Devices and systems that can be used with increasing precision are able to react to environmental conditions and can be controlled in the context of the end application.

The advantages that industry, users and consumers expect from these developments speak for themselves: the massively increased power densities and more compact dimensions of the devices result in broader application areas and more possible uses. Today, infinitely adjustable controls combined with powerful data-acquisition functions are expected: even for simple applications that until recently involved only a simple ‘on/off’ circuit.

Figure 1: The har-flexicon connector system allows single connectors at a 1.27mm pitch to be quickly mounted onto a PCB 

Figure 1: The har-flexicon connector system allows single connectors at a 1.27mm pitch to be quickly mounted onto a PCB

These developments in miniaturisation and multi-functional devices have an impact far beyond the single device area. The systematic development and networking of different data worlds offer significant benefits within an organisation in areas such as corporate and cost control, helping a company’s control of production, energy and cash flows. Service and maintenance work can be arranged more effectively, and the associated costs can be minimised.

Modular concepts

One result of this trend is an increasing use of modular devices, which in turn present challenges in terms of field installation, service and maintenance. Even in conventional service and maintenance work, the increased use of modules and devices in the field that must be matched by the capability for swift and simple field installation and exchange without special operator training or the need for special tools.

These challenges extend down to the level of individual devices and into peripheral areas such as the printed-circuit board and the termination technology required to link the device to the PCB. Powerful miniature devices require powerful termination concepts which, most importantly, need to be implemented economically. Customised production, complex manufacturing techniques or complicated assembly methods that may be subject to human errors in the field cannot survive in an economy that is based on the effective use of resources, and that favours economical solutions.

Figure 2: The use of IDC connection technology makes field installation possible without the need for special tools

Figure 2: The use of IDC connection technology makes field installation possible without the need for special tools

In order to address these challenges, The Harting Technology Group has investigated new concepts and solutions for single- strand wiring of PCBs that are also powerful and reliable, economical and easily installable in the miniature range. The result is an interconnection concept known as har-flexicon (Figure 1).

Using this device, it is possible to connect flexible single conductors using insulation displacement connection (IDC) technology without the need for separate wire-stripping. This process allows simple disconnection or connection of the connector without the need for complex re-contacting. With a pitch of 1.27mm, the connector’s height is only 5mm, measured from the upper edge of the PCB. In spite of its compact design, the har-flexicon can be operated very simply and swiftly. The mating reliability is extremely high thanks to the use of error-free contact retention, and multiple insertion and detachment steps are very straightforward.

No tools are required to detach or insert the har-flexicon in the field. This reduces costs significantly, especially in the maintenance and service area, and as the connection can also be executed swiftly under difficult environmental conditions.

This is currently the most compact field-installable PCB connector available for use with single wires. The 1.27mm pitch is only half that used with conventional termination technology and the device is also suitable for universal use in transferring I/O signals in sensor systems and actuating elements.

User benefits

This concept for the connection of PCBs in industrial devices offers several advantages over conventional solutions, including swift single-strand termination for flexible processing in the field without the need for special tools, compatibility with surface-mount technology, miniaturised pitch size and a high stability level.

Figure 3: Lateral surface-mount fixings offer superior strength for PCB mounting using SMT production processes

Figure 3: Lateral surface-mount fixings offer superior strength for PCB mounting using SMT production processes

The har-flexicon is a logical continuation of Harting’s har-flex product family, which provides rugged and economical board-to-board connection technology. As a new generation of PCB connectors, both series are setting the future standard for the efficient PCB connection and rugged miniaturisation that state-of-the-art devices require in industrial applications. Together, these connector series provide a complete range from device connectivity to device internal wiring to board-to-board connections. A standard connector design results in uniform devices.

The new termination concept can be processed by machine and can be applied to the PCB using the same surface-mount technology used for all other components on the PCB without any compromise on stability. In other words, with the PCB now becoming the core component in industrial devices, standard machine processing of the components will become the accepted norm.

Traditionally, electronic components such as passive devices or ICs have been mounted on the PCB using surface-mount processing as the standard. Connectors, however, have been the last devices to be mounted using conventional wiring, largely because soldered connections display greater strength for through-hole plating.

To overcome the problem of SMT connections being less stable, the new rugged connector concept uses extensive lateral surface-mount fixings which allow it to absorb larger pulling and insertion forces. This is a key advantage, particularly for detachable connections in which repeated and simple plugging must be ensured. This approach makes it possible to assemble the PCB terminals in the same operational process and with the same equipment as the other surface-mount devices because the required stability is ensured.

Figure 4: Harting’s har-flex and har-flexicon ranges together offer a complete connectivity solution for device-to-board and board-to-board applications

Figure 4: Harting’s har-flex and har-flexicon ranges together offer a complete connectivity solution for device-to-board and board-to-board applications

This approach makes it possible to ensure clear advantages through swift and standardised machine processing. It also eliminates the possibility of weak points inherent in the soldering of individual wires, such as limitations of the heat input on to the PCB and fluctuations in the processing quality.

It also becomes possible to use serial machine processing with the SMT components being delivered in tape packaging. The high temperature materials in the insulating inserts also allow safe processing in the reflow process.

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