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What is rugged? Part 2: Essential rugged features not in the standards

This is the second part of our article on What is Rugged? See part one, covering some of the specifications that define tests and limits for the strains rugged equipment can withstand, here.

In addition to the test variables specified by the IEC and MIL standards covered in part one of this article there are a number of other criteria which are necessary for any device to be given the label “rugged”. These are not defined by any industry standards, but are just as important to keep in mind when it comes to rugged equipment.

Power supply
Computers mounted in forklifts or other vehicles are particularly prone to experiencing power outages of various kinds. Every time the vehicle starts up power outages can occur as all the power is directed to starting the engine, while total power failures happen when the battery is disconnected or changed. When an electrical forklift is running intensely, the supply voltage levels are variable and the polarity can even be reversed, making for very difficult power supply conditions for vehicle mounted terminals. To deal with these problems, computers that are truly rugged must incorporate an isolated power supply (i.e., with electrical separation) to manage shifting voltage levels and prevent ground loops in an electrical truck. Another must is a built-in UPS (Uninterrupted Power Supply) solution that keeps the terminals running when the main power supply is interrupted, for whatever reason. Additionally, they should have a power supply with a wide voltage range to enable use in many different vehicle types.

WiFi connectivity
As cloud- or server-based software solutions and terminal emulation become more popular, rugged computers need to maintain reliable wireless connectivity to ensure the computer system functions properly and operations run smoothly. This can be tough in the difficult conditions presented by the wide areas of shipping ports, inside warehouse buildings with large steel structures, or when the computer is mounted inside a truck cabin. Technologies to look for in vehicle computers that improve WiFi connectivity include dual diversity antennas, antenna designs such as PIFA (planar inverted-F antenna) and, for the most challenging environments or when the computer is used in a steel cabin, external antennas. Often, the need for external antennas can be determined only after initial installation. Having the option to add the antennas onsite, after deployment, therefore means decreased risk of investment and potential long term savings.

The reliability of WiFi connections depends not only on the hardware, but also on the available infrastructure, the technology generation used, the number of access points, system settings, etc. Since every application presents its own challenges, the only way to assure that a computer’s WiFi connection will be sufficiently stable, is to test it in the field. Hence it’s a great advantage to choose a supplier with good knowledge and experience from within the industry.

Sunlight readability
A large number of rugged industrial applications demand both indoor and outdoor operation of the vehicle computer. In this case, the ability to clearly see information on the display regardless if it’s inside or out in bright sunlight is vital. Ordinary consumer tablet displays are often not bright enough to be readable in outdoor situations. Brightness is measured in NITs, where 1 NIT equals 1 cd/m2. The recommended specification of a computer display that will be used outdoors is 800 NITs or more, but since even displays with the same specification vary a lot, users are advised to always evaluate the computer in its real environment.

Electrical noise
Electrical noise is a big issue for all sensitive electronics used around heavy machinery, such as large motors, especially older equipment installed before sensitive microelectronics were introduced. Rugged PCs for mining, transportation and industrial applications therefore require adequate immunity to electrical noise, and this may be done using a combination of appropriate grounding and shielding. Thorough testing should be carried out in the field to ensure protection against interference is adequate for the rugged computer to be used in the real application without any problems.

System performance
The above mentioned aspects of a computer, combined with processor performance and ergonomic design factors, are critical to how reliably the unit functions in the real world, and have an imperative impact on user experience and worker performance.

Save time and money by testing the rugged computer in its real operations before making a final decision 
In the first part of this article, you learned about some international industry standards that define the level of ruggedness in computer hardware. Knowing about standardized measurements, as well as the other crucial aspects of rugged PC’s covered in this second part of the article, will be valuable when starting to evaluate rugged equipment. However, no matter how many tests are performed, or what the product specification states, in the end what truly matters is that the computer functions reliably in its everyday business environment. To assure the equipment works for your application, you should always test it in real operations before making a final purchasing decision; doing this will in the long term save you time, money and annoyance from badly functioning equipment.

 

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Per Holmberg

Per Holmberg

CEO, JLT Mobile Computers Group

July 6, 2017

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