Figure 1. The HIT-W121 slim, touchscreen terminal, with its “bezel-less” design is suited for use in medical environments.

I’ve written my share of tear down articles before, but this is my first for a device aimed at the medical market. If you’re not familiar with the term, a tear down is an analysis of the design of a shipping-end product—a slim touchscreen terminal, in this case. It’s done by literally taking the device apart and closely examining the components, then conducting extensive interviews with the team that designed the device. Questions include: Why did you choose these components? In retrospect, was it the right choice? Why did you choose the operating system (OS) you did? Would you have done anything differently if you had a bigger budget or more time to work on the design?

The Advantech HIT-W121 terminal made for an interesting tear down because it shares many of the same characteristics of a traditional computing platform, yet it needs a few extra bells and whistles to be appropriate for medical applications (see Figure 1). It has an 11.6-in. single-surface touchscreen display; is powered by an Intel Atom D510 microprocessor; supports Windows, Android, and Linux OSs; and is built with a compact, VESA-mountable form factor (see Figure 2).

The 1.6-GHz D510 microprocessor contains dual cores. Advantech is looking at a similar microprocessor, the N450, but that will likely be held for future generations.

“All of our medical products are based on Intel microprocessors because that’s what our customers prefer,” says Joseph Chung, a product manager at Advantech. “And from our perspective, it’s still easier to work with Intel. Because we are one of their premier partners, we have one of the early access kits, and the newer designs will be easier for us as compared to something like AMD. Basically, the choice comes down to the maturity of the processor and the amount of support we get from Intel.”

Figure 2. The key components of the board, including the Intel D510 microprocessor, are shown here.

Customers, he says, are also familiar with Intel, thanks to the company’s aggressive marketing.

“Whenever they launch a new product, everyone knows about it and wants it in their product,” Chung says. “Also, the customer’s engineers have been using Intel for a long time.”

Advantech has designed some of its products with ARM-based processors, but the company feels Intel products provide the horsepower it needs, especially in the medical sector. This particular product was developed in Taiwan, where Advantech houses one of its design facilities. The HIT-W121 was developed over about nine months, including all the certification and debugging.

Besides the D510 CPU, another key component is the processor’s companion chip, or I/O hub, the ICH8. The part’s functions include support for PCI Express and local bus, ACPI power management, and enhanced DMA. It is also available with up to 10 USB ports, as well as support for high-definition audio and a Gigabit Ethernet controller.

Other features of note are the compact flash memory, medical power adapter, and a touchscreen with true widescreen LCD, which is a key differentiator for this product. The touchscreen controller comes from a vendor in Taiwan.
The design is sleek, with no bezel used in the front-panel assembly—even when integrating the touchscreen with the LCD. This makes the product easier to clean.

Connecting Peripherals

The HIT-W121 was designed so that peripherals, such as an RFD smart card reader, can easily be connected. For connectivity, the system employs a mini-PCI Express wireless card. It’s also possible to connect to general packet radio service through a mini-PCI Express card.

“We decided to take the module approach as opposed to building the technology right onto the motherboard because the lifetimes of some of these modules are not too long,” Chung says. “And for medical, you have to certify the product with those modules. So if there’s an issue with one of the modules, you have to submit the system for recertification. That was an issue for some of our customers, so we prefer not to embed the modules into the system.”

Advantech is not an FDA-registered manufacturer, so it doesn’t get involved with the certification process. Its customers must take on that burden. But Advantech does include all the safety and electromagnetic compatibility features required by UL and Federal Communications Commission Class B.
 

Storage Options

This particular unit was built with a rotating disk drive, but users have the option to plug in CompactFlash memory. OEMs can also spec in a 2.5-in. solid-state drive (see Figure 3). The unit is typically used in a stationary environment, so the rotating media generally doesn’t present a problem.

Figure 3. OEMs can choose between various media types, although rotating storage is most often used.

At the back of the board, I found a fairly hefty heat sink, which Advantech calls an integrated heat sink. It attaches directly to the CPU and chip set. Most OEMs will mount the system with a swing arm. That also helps with heat dissipation, as the heat can go through the mount or arm.

Powering the Device

While the HIT-W121 can be built with a battery backup, it’s not designed to run directly from a battery (total system power is about 20–30 W). The backup will retain the platform’s data in the event of a power outage. It can supply power for 20–30 minutes.
In most cases, the device is installed on a medical cart or bedside. If on the bedside, there’s no concern about power because it gets plugged directly into the ac power source. It should also integrate well on a cart, because most carts have a high-power option.

“The most challenging part of a design like this one is the certification process,” Chung says. “The design process itself usually isn’t too difficult because we’ve been doing this for a long time. Detailed reports must be sent to the certification bodies, and that could take a long time. When we submit the risk management files, for example, all the different use-case scenarios need to be profiled.”

The most requested change from customers for the next generation, according to Advantech, is the removal of the smart card reader tray, on the right side of the unit. It was inserted into the design mostly for customers in Asian countries, where a lot of smart cards are used. In the United States, however, where smart cards are not nearly as popular, the tray is basically unused.

The HIT-W121 ships with Microsoft’s Windows XP Embedded operating system. Customers are provided with a standard image. The platform can also run Android 2.2 and will be moving to version 2.3 shortly. Some customers request a Linux OS, but that can get complicated from a support perspective, as there are so many different versions of Linux. And if customers—particularly systems integrators—are interested in a bare-bones product, Advantech is willing to provide that, as well.

Richard Nass is the director of content for UBM Canon’s medical device brands, including MED.

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