Do COM Express® Single Board Computers Have a Place in IIoT?

Select PICIMG open standards, including COM Express, get a boost from the IT industry to engage in the Industrial IoT using a RESTful API.

Computer on Modules (COMs) have been around for some time. Combined with open standards, devices in this category reduce waste, minimize design risks, and increase ease-of-use and interoperability. COM Express® refers to Small Form Factor (SFF) and Single Board Computer (SBC) modules, platforms, and their specifications. The specifications reside under the oversight of the PCI Industrial Computer Manufacturer’s Group (PICMG), a consortium of equipment makers, component suppliers, system vendors, and end users for the embedded (non-desktop) computer market. COM Express was created to provide a standard path to increasingly higher performance platforms featuring high I/O bandwidth in an extremely compact form factor.

Figure 1: IIoT incorporates industrial sensing that is everywhere, advanced analytics, and IT technologies.

The first COM Express specification was released in 2005, with the most recent COM Express Rev 3 released in 2017. COM Express specifications are maintained with recent chipsets and serial signaling protocols, including 10GbE, SATA, PCI Express (PCIe) Gen 3, USB 3.0, LVDS, CAN, HDMI, and more. COM Express is much more versatile than other standalone SBCs, however. COM Express is defined by an open standard to be used as either a standalone single board computer or as a processor mezzanine that can be plugged onto a carrier board that contains application specific I/O. COM Express is future-proofed in that as technology improves, performance upgrades are as easy as plugging a COM Express module into a carrier board. COM Express demonstrates its versatility with a variety of form factors and board sizes defined in the standard, as well. COM Express modules range from compute-intensive to general-purpose CPUs to low-end CPU modules that are commonly re-used.

COM Express is used in a wide range of markets, including commercial, industrial, medical, transportation, gaming, and military/aerospace markets. Target applications include industrial control, data acquisition, medical, human interface devices, communications, and more. Applications requiring high-speed connectivity can use up to four 10GbE interfaces and up to 32 PCIe lanes, which is ideal for high bandwidth applications in video surveillance, data centers, or industrial quad-play services (data, voice, video, and control) that might include high definition IP cameras for real-time monitoring. Rugged versions of the small form factor COM Express are found in railway, military, avionics, and remote data acquisition applications.

It stands to reason that COM Express is well-suited to engage the Industrial IoT (IIoT) for industrial automation. For example, a fully automated “smart” factory has instrumentation everywhere, with monitoring and control of the manufacturing process as well as warehouse and stockroom. All systems leverage the same IT methods and systems so that detailed relationships can be established throughout the entire factory, from stockroom to manufacturing line to warehouse.  Douglas Sandy, CTO & Vice President of Technology, PICMG, recently authored a white paper on the topic, Industrial Internet of Things: A high-level architecture discussion. States Sandy, “Because the factory control and the inventory control systems both leverage IT methodologies, integration and analysis between the two domains is easily achievable, allowing actual factory production rates to factor into intelligent purchasing and inventory management algorithms.”

Figure 2: Smart Factory / Industry 4.0 / IIoT (Source:

PICMG’s open standards are under scrutiny for points of integration with IT to offer the benefits of IIoT.  Sandy points out that, “COM Express is well suited for small gateway control and IIoT controller functions. CompactPCI Serial may also have a play in larger IIoT controllers and control gateways where scalability is required. COM Express provides the highest performance of the many small form factor standards and products available. When used in conjunction with an I/O base-board, COM Express can easily interface to the wide array of legacy industrial control interfaces deployed today.”

Where does PICMG fit into IIoT?
PICMG’s COM Express and CompactPCI Serial have potential in IIoT. However, a system view is where participation starts. “As important as hardware is, the software meta-data model is key to the success of Industrial IoT and provides the best place for PICMG to contribute to the overall adoption of IIoT.” A metamodel is a model of a model, much like pseudocode uses descriptions of blocks of code to represent how a program is architected. The process of metamodeling includes an analysis followed by development of frameworks, constraints, models and theories that help model a predefined class of problems.[i]

PICMG recently announced a partnership with the Distributed Management Task Force (DMTF) to incorporate the IT side of the IIoT equation. Founded in 1992, the DMTF is an IT standards body that “creates open manageability standards spanning diverse emerging and traditional IT infrastructures including cloud, virtualization, network, servers and storage.”[ii]  DMTF has a tool that is suited for enabling PICMG technologies to engage the IIoT perspective as seamlessly as possible. DMTF’s Redfish® Application Programming Interface (API) is a standard API that simplifies management of converged or hybrid IT. Redfish uses common web services standards “…to expose information directly to the modern tool chain.”[iii]  The “tool chain” being the set of software development tools that are used to create software products….or industrial control loops. Industrial automation and data centers have a lot in common. Unfortunately, they have evolved on separate paths using the same technologies. IIoT is a marriage of industrial automation and the type of information technology typically associated with data centers.

Per Sandy, while metamodeling “…is not directly aligned with the hardware platform management efforts of the past, PICMG has domain expertise in this area that is directly applicable.”  PICMG created a software specification in Hardware Platform Management (HPM) for AdvancedTCA and later used in MicroTCA.  DMTF is an industry standards organization that has developed the Redfish schema for data centers. PICMG is exploring the best way to work with DMTF with an aim to ultimately provide a unified data model for IIoT within the PICMG scope. The Redfish API uses Representational State Transfer (REST) technology, which builds upon the existing systems and features of HTTP. Thus, Redfish uses HTTP requests to simply PUT, GET, POST and DELETE data.

Sandy identifies the interface between industrial automation and IT. “IIoT sensors present themselves as intelligent, managed devices over the factory network using the common meta-data model. Using RESTful application programming interfaces, sensors may be monitored and controlled using standard IT methodologies.”

Standards for Industrial IoT?
Businesses are leveraging the IoT for smarter applications by combining industrial automation networks, converging to IIoT. IIoT must be more robust than IoT, thus extends beyond traditional industrial automation in that it synthesizes information gathered from persistent sensing, applies advanced analytics, and uses standard IT technology to do it.

Computing technologies harbored at PICMG are suited to the IIoT due to their robustness, interoperability, and present installed base in industrial settings. PICMG is open to accelerating the adoption of the IIoT by providing open specifications and design guidelines meant to aid in creating IIoT solutions that integrate well with PICMG computing technologies. As such, the 24-year-old PICMG consortium is working to leverage strengths in industrial computing by building partnerships with IIoT-focused standards organizations. According to Doug Sandy, VP of Technology for PICMG, “the largest barriers to commercial IoT rollout today appear to be technological (security), sociological (privacy), and economic (cost vs benefit)….its immediate application may be best suited to areas where these barriers are less significant. The industrial markets that PICMG serve are such a place.”[iv]

In a study conducted by Morgan Stanley and Automation World magazine, the top challenges for IIoT are cybersecurity, lack of standardization, and existing installations of legacy systems.[v]  PICMG aims to be a catalyst for mitigating these challenges to IIoT. As Sandy’s paper states, “Large industrial automation suppliers are not incentivized to embark on open standardization because it loosens the customer’s dependence upon their proprietary solutions. Smaller automation suppliers lack the industry clout or size to take on such an ambitious undertaking. This is a task best suited for an industry standards organization, and one which PICMG is well equipped to handle.” PICMG is on its way, recently announcing that a work register has been created between PICMG and the DMTF to collaborate on IIoT.

Justin Moll, Vice President of Marketing for PICMG, makes note as to why coordinating with organizations outside the industrial norm for PICMG is important. “The DMTF is an industry standards organization striving to simplify the manageability of network accessible technologies. PICMG is creating a meta-data model to bring IoT interoperability to the sensor domain.  By working together, PICMG can leverage the existing Redfish APIs that are already well known in the IT world to simplify our model building effort.”

Will IoT ever have a body of standards that covers it all? Not likely, since IoT’s range of applications, components, vendors, and services is so broad. However, it is likely that standards groups like PICMG will create interfaces for interoperability that cover the vast majority of vendors’ products and schemas. PICMG’s specialty is “interoperable interfaces.” This concept increasingly applies not just to hardware, but software as well.

[i] “Metamodeling.” Wikipedia, Wikimedia Foundation, 3 July 2018, Accessed 5 July 2018

[ii] “Distributed Management Task Force, Inc.” DMTF,

[iii] “Distributed Management Task Force, Inc.” DMTF,

[iv] Industrial Internet of Things – A high-level architecture discussion (PDF), Douglas Sandy,

[v] Morgan Stanley. (2017). Automation World Industrial Automation Survey.


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