Bringing PC-based productivity gains to various applications

Reliable technology delivers productivity gains in many ways but, arguably, the singularly most significant technological development in modern times was the PC. Its open interfaces and software accessibility, based on a common hardware platform most often enabled by the x86 architecture, has delivered productivity gains in every office in the world and their benefits continue to ensure their use in an ever wider number of vertical markets. While sales of consumer computers may be under pressure from various angles, demand for professional, rugged and industrialised computers has never been stronger.

Despite the industrial PC market having unique requirements, predominantly high-reliability, consumer expectation means it isn’t immune to certain pressures, such as demand for reductions in size, weight and power. Through the continued investment and support of semiconductor and module manufacturers, developers are well equipped to meet these demands, leading to innovations that further fuel demand for ruggedised PCs.

While the application may vary from medical to manufacturing, baking to building or automotive to automation, a fundamental desire for portability unites them. And when something is designed to be portable it follows that it must be as small as possible.

No disassembly required

Developing mobile computers specifically to be mounted and operated within commercial vehicles carries with it a number of requirements, one of which is the ability to quickly locate and remove the unit from inside a vehicle. The vibration experienced by equipment mounted within a moving vehicle such as a lorry or tractor can be extensive, particularly when the operating environment is less than conducive to sensitive electronic components. To deliver reliable and secure mounting, many mobile PCs use the industry-standard VESA mounting system. While this provides sturdy support, it doesn’t facilitate easy removal of the unit; the connections needed to operate the computer, such as power and peripherals, are essentially hardwired in to the vehicle, as is the unit itself.

To address this, a new method for mobile computer docking has been developed, one that allows the PC to be easily removed from the vehicle without the need for any disassembly. The solution JLT has developed is called QuickLock and it allows all power and data to pass through a single 60-pin connection made between the computer and the docking station. The computer is held in place with an innovative sprung-loaded ball and socket concept that effectively absorbs any manufacturing tolerances, prohibiting the vibration introduced by the vehicle’s movement from disturbing the mechanical and electrical interface, thereby maintaining a reliable connection between the computer and the docking station. This allows the docking station to be permanently fixed within the vehicle, while still enabling the computer to be removed with ease. The electrical and mechanical specification of the connector is intended to allow in excess of 10,000 dockings to be made/broken without failure.

Figure 1 - Schematic view of VERSO+ 10 docking station

A key design parameter imposed on teams responsible for developing vehicle mounted technology is to deliver a smaller solution without compromising on functionality. Often, the size of the casing for a portable PC with an integrated LCD screen, for instance, can far exceed the screen’s dimensions. This can often be the price paid for ruggedisation, however such compromises are avoidable if the design is undertaken with the objective of offering something more than just a smaller screen size.

The challenge for designers may be to accommodate a 10" screen in the overall dimensions of a PC with an 8" screen, for example. In many cases, the screen size would determine the overall case size but in reality the goal should be to make the case size as small as possible while maximising the screen size. The reasoning behind this reflects the fact that the space available for in-vehicle PCs is invariably limited, even in large machinery. Developing a 10" PC that takes up no more space than an 8" alternative requires careful mechanical design. Moreover, the fact that the PC is normally expected to operate without any forced air cooling, relying solely on convection, also imposes design constraints, particularly as the space available within the casing will also be limited.

Because the casing is as physically small as possible, the mass of metal available to conduct the heat away from the electronic components will also be reduced. This not only introduces the need to employ high grade aluminium for the case, but also the use of a high performance thermal interface material that will allow the heat generated by the electronic components to be more efficiently conducted to the case and, from there, radiated to the environment.

Accommodating the electronic assembly, including storage, battery and wireless antennas (if wireless connectivity is required) also demands manufacturing processes to adhere to tighter tolerances, often providing just 0.1mm clearance. This can be further complicated if user access to the wireless antennas is required, which is often the case as it provides the option to replace internal antennas with external versions to maximise wireless communication signal strength, if the operating environment deems it necessary.

Electronically elite

Of course, at the heart of any PC is the processing subsystem. A popular solution chosen by many manufacturers is to adopt a modular approach, often based on the COM Express Compact (95x95mm) format, supplied by companies such as congatec. The form factor offers all the processing performance of a regular PC but in a much smaller footprint, perfect where size is critical. And because COM Express modules are developed to meet the demands of industrial applications, their use in a fanless enclosure is supported.

The approach to using COM Express requires the module to be mounted on a motherboard, which in most cases is developed by the PC manufacturer. The motherboard isn’t like a regular desktop motherboard, as almost all the functionality is integrated on to the module, such as display drivers, network connections and USB peripherals. However, often the motherboard is used to accommodate additional features not provided on the COM Express module, such as wireless communications including Bluetooth, WiFi and even cellular connectivity such as 3G/4G.

JLT faced all of these challenges when developing a 10" vehicle mounted computer and the result is a 10" mobile PC that is the first to employ the QuickLock docking solution. Additionally, inside the docking station, all power and signal connections between the PC and the I/O ports pass through a single, flexible PCB, thereby reducing the risk of mechanical fatigue or stress on electrical connections and prolonging service-free operation. Due to the restricted space in both the PC housing and the docking station, the use of flexible PCBs created an opportunity for innovation in both design and reliability. Taking the Ethernet and USB connections directly off the COM Express module and to the docking connector overcomes a problem some industrial PC manufacturers still encounter, through the use of a hub between the processing module and external connectors. As well as adding size and cost, this can introduce additional mechanical and electrical instability, a flexible PCB removes this potential weak point and further increases reliability by design.

Thanks to the modular approach, the processing power provided can be easily upgraded, by simply replacing the COM Express Compact module with another. This is a key benefit of using an industry standard such as COM Express (which is maintained by the independent consortium, PICMG). The module selected for the VERSO+ 10 is based on a dual-core Intel Atom processor, but can just as easily accommodate the latest i5 core if required. Similarly, higher capacities of RAM can be added, although the VERSO+ 10 offers 4GB of RAM as standard.

The design of in-vehicle PCs imposes many constraints; mechanical and electrical parameters are unlike those of any other application area, while the harsh environment introduces its own unique challenges. Despite this, the productivity benefits they offer ensures their use will continue to increase. In order to meet customer demand for reliable, small, silent, secure and efficient solutions developers need to embrace these challenges and deliver innovative products that offer greater functionality, take up less space and provide intuitive, reliable operation.