Wireless measurement and data acquisition

The embedded developer b-plus was looking to migrate its XScale-based visualisation client, which is designed to be the mobile HMI for Zigbee measured data, to an Atom-based platform, to benefit from enhanced graphics and processing performance, easier long-term scalability in performance and openness in software development. One major question needed to be answered: what is the most efficient hardware platform for this application?

Over the past decade, working with x86 technologies on small professional mobile devices was right out of the question due to two major problems: x86 was too expensive and, even more importantly, it had become too power hungry as its performance increased.

Thus, engineers needed to work with dedicated microcontrollers that were designed especially for mobile devices. One attractive platform for this was, and still remains, the XScale technology.

This is a platform b-plus that had been used in the past, so the company developed its mobile Zigbee based on the technology.

But things have changed in the last two years, since the launch of the Intel Atom processor. Now even x86 technologies fit the needs for mobile devices powered by batteries for an entire workday. Thus, the evaluation of the right platform is today a very different story compared with the past.

Users now have the choice of either proceeding with a RISC-based solution, such as XScale or ARM, or switching to an x86 technology. Arguments for x86 technologies are the scalability of performance over processor generations and the openness with respect to software.

However, it is not only the x86 standard that is attractive to developers but also the standards of different form factors on the board or module level that are available as COTS components. This one factor is a major plus that truly separates x86 from all other SFF microprocessor platforms.

There are almost no open and widely accepted module- or board-level specifications available for XScale or ARM processors. Most engineers, therefore, design their own dedicated boards or use modules that have almost no successors.

However, this is not really an effective use of development resources, because a lot of time and money then goes not only into the software design but also the hardware design. With x86 technologies this is all completely changed.

The company now has an abundance of options, not just in software but also in hardware. It could resort to making a dedicated design from scratch as it has done in the past, or it could step up to a COTS x86 platform to reduce hardware development costs to a minimum, which, in the end, is what the company chose to do.

Now that an x86-based board was required, the question of which x86 form factor would be suitable immediately came into play because the freedom of choice to reduce development costs makes evaluation of the right board-level platform most important.

Standard board-level products such as traditional motherboards based on ATX specifications are simply designed primarily for desktop applications and thus are standard with an assortment of interfaces not required for mobile devices.

On the other hand, the choice of a fully custom board had proved in the past to be too costly to develop. What was needed was an ‘in-between’ option that offered the flexibility of a custom board development with the low cost of a standard solution. B-plus found such a concept in computer on modules.

A computer on module (COM) is an embedded computing core built on a single circuit board, that contains the processor, RAM, I/O controllers and all other required interfaces for basic operation of the system. Additional features and all physical interfaces for the periphery can be added through a custom-specific designed carrier board for these modules including the option to design expansion card slots to use COTS components for the dedicated interfaces.

Thus, COM-based systems are tailored to suit an application’s needs. The use of COMs lowers hardware development costs, which normally make up to 30% of all development expenses. It also reduces the unit cost in series production due to the fact that only the required components are soldered to the board.

With the decision for COMs, the freedom and, therefore, also the evaluation requirements do no end. COMs are available in many different variants. Some are supported by only one of a few smaller vendors. Others are globally accepted and supported by well-known vendors. So again an evaluation process has started.

B-plus ultimately decided on the nanoETXexpress platform from Kontron which is based on the COM Express specification defined by PICMG.

The main benefits are the most globally accepted specification, a huge designer community, the design guides offered by PICMG and, finally, the compact, highly reliable hardware design, which can handle the heat produced by an LCD panel and the conditions in industrial and even outdoor environments and, additionally, offers the most openness and scalability to suit future needs.

By choosing nanoETXexpress, b-plus could now profit from the new openness it afforded, not just on the software and x86 processors but on the hardware itself at the board level.

The new eVISIO7 panel concept from b-plus, which can be used in mobile and stationary applications, is today based on the company’s own ePDA carrier boards with credit card-sized Kontron nanoETXexpress computer-on-modules for scalable CPU implementation.

This makes the panel PC a flexibly scalable Open Frame solution for a wide range of applications. One specialised application area is wireless data acquisition for, eg, measuring air pressure, temperature or vibrations even of moving objects. Owing to the wireless and battery-driven sensors, they can be installed on mobile devices and, with this, significantly reduce the number of cables required for complex test and measuring set-ups.

For the new 7″ system concept with bright touch TFT, b-plus implemented COM Express compatible, credit card-sized nanoETXexpress computer-on-modules with x86 Atom performance. The implemented ZigBee-based protocol allows reliable data transmission.

In various mobile measurement applications, measurement data is synchronously transmitted from several sensors to a USB coordinator on the eVISO7. This data is then logged into tagged memory and prepared and visualised on an Adobe Flash-based application. The communication between tagged memory and visualisation runs over TCP/IP, so that this approach is also suitable for remote data acquisition.

By using Flash, the effort that has to be put into programming, compared with natively programmed user interfaces, is kept to a minimum, and implementing user-specific features such as corporate design and usability can be put into practice more effectively.

With this concept, it would also be possible (after porting) to use the new Windows embedded CE 6.0 R3 release with native Adobe support for FlashLite 3.1.0.

Besides its high software compatibility, the Atom processor Z530-based eVISIO7 concept from b-plus also exploits the advantage that data logging and visualisation can be run simultaneously and not have any influence on the other tasks, thanks to hyper-threading.

Furthermore, when sourcing the right module for the panel PC carrier board, PICMG compatibility and the robust design, along with low power dissipation of the Atom-based module, were of importance.

B-plus also offers the carrier board with user-specific interfaces and ones designed especially for mobile industrial applications. Next to the nanoETXexpress computer-on-modules, b-plus also implemented a smart battery system based on the smart battery management system MARS (mobile application platform for rechargeable systems).

With Kontron’s MARS system, developers can add pre-designed layout and circuit diagrams for smart battery systems by copying and pasting them into their own carrier board layouts. The applied building blocks have already been tried and tested, so hardware evaluation, circuit diagram design and the otherwise painstaking collection of different components is greatly simplified.

Besides this, the application developer does not have to first complete the entire application-specific hardware to program the corresponding software.

With the Kontron MARS reference board, the software development can be launched straight away and tested on the development platform. Due to this ‘in-the-loop’ development, the developer immediately knows which components will be employed and can optimise the programming code in parallel to the hardware configuration.

By combining computer-on-modules and MARS, developers like b-plus are able to concentrate on their core competencies and save development time.