Industrial PCs offer a range of processing capabilities, form factors and certifications that engineers must consider when implementing edge computing strategies in new applications or legacy systems
The advantages of edge computing in cloud-connected plants are numerous, and at this point, they are fairly well known. By gathering and analyzing process data on local controllers before sending it to the cloud, engineers can visualize production data on HMIs, monitor machine health and schedule predictive maintenance, as well as minimize data upload costs. It is also well known that edge computing relies heavily on networks, software, algorithms and communication protocols, such as MQTT, AMQP or OPC UA.
However, an often overlooked aspect is the actual controller hardware. While many factors affect the success of edge computing applications, the hardware determines in many ways whether the applications are even possible. It is important to install a high-quality PC-based controller that can handle the advanced data acquisition, processing and cloud communication tasks that are crucial when designing and commissioning new, IoT-ready machines. Open PC-based hardware is even more crucial when retrofitting legacy equipment with edge computing capabilities, which requires additional steps to tap into plant data.
As a result, there are many key considerations when selecting an appropriate edge computing device. These include a device’s ability to fit into cramped control cabinets, the quality of housing materials, processing power and the ability to divide tasks among CPU cores. The right hardware can vary by application as well. Understanding the available options is the first step to ensure a successful edge computing project.
Processing power and customization are core concerns
Controllers used for edge computing must handle large amounts of data while completing other automation tasks. Today’s IPCs provide many different levels of processing power and memory, ensuring a solution is available for each application and price point without becoming superfluous. The IPCs should also offer enough flexibility for customization in regards to how they utilize the available processor cores.
Edge computing devices can feature a variety of processors — from a 400 MHz, single-core ARM Cortex™ M7 to a 1.6 GHz, quad-core Intel® Atom™ and beyond. The C6015 ultra-compact IPC from Beckhoff is one such device, and the robust IPC family that sprung out of it offers additional scalable options and even a machine-mountable, IP65/67-rated device, the C7015 IPC. Many-core IPCs and embedded PCs feature more advanced options, such as 2.2 GHz Intel® Xeon® processors, which can boast anywhere from four to 40 cores.
When examining these specifications, it is also important to look for automation software that allows users to dedicate tasks to individual cores and make the CPU run at peak effectiveness. This will also ensure the IPC can multitask and accommodate more functions on one device. With a quad-core CPU, for example, isolating the PLC on core 0, motion control on core 1 and HMI on core 3 allows an engineer to dedicate the final core solely for edge computing activities.
Local data storage and RAM capabilities also fall on a wide spectrum. At one end, some IPCs offer anywhere from 512 MB MicroSD cards to 960 GB solid-state drives with the option to add a second storage device for additional space if needed and anywhere from 1 GB up to 64 GB of DDR4 RAM. On the other end are even more capable IPCs that provide up to 1 TB DDR4-RAM EEC and 4 TB or more on 3 1/2-inch hard disk drives. As with processing power, the specific application determines the amount of storage required. Cutting-edge installations with advanced vision systems, for example, will require more memory and processing power, while less complex projects will not.
In greenfield edge-computing applications, IPCs will likely control entire machines or lines in addition to analyzing and making corrections based on real-time process data. Implementing this level of control in a brownfield setting would require a retrofit, which may not be worthwhile to engineers simply hoping to gather and leverage more process data. Without resorting to a complete rip-and-replace, an IPC can easily gather data from the legacy fieldbus and/or PLCs, filter it, analyze it using advanced algorithms and then send the required information to the cloud.
Form factor and material choices for industrial edge computing
The edge device must be well-suited to the factory and enclosure. Production environments run the gamut from very hot to very cold, depending on what is being manufactured, and existing control cabinets often cannot accommodate much additional heat. IPCs and embedded PCs in compact form factors can withstand temperature extremes and support countless application types.
IPCs with rugged metal housings can integrate into any space with the option for cabinet installation or DIN rail mounting. The durable metal construction ensures they are ready for use in any plant environment, and when outfitted with a heat sink or fan, it also minimizes the risk of overheating the enclosure. In addition, selection of certain processor series, such as Intel® Atom™, can minimize the risks involved with high temperatures. A broad selection of connector ports, such as gigabit Ethernet, USB 2.0 and 3.0, DisplayPort, along with scalable memory and RAM make these IPCs excellent edge devices for new applications that demand the highest performance levels and for existing systems that require edge capabilities.
When implementing an entirely new control system, embedded PCs offer additional benefits. These DIN rail-mountable controllers connect directly to I/O modules in the control cabinet, further minimizing hardware footprint and cabling requirements. Equipped with either industrial-grade plastic or metal housings, embedded PCs can operate with minimal heat dissipation and in a range of temperatures, often spanning as high as 50 degrees Celsius and down to -25 degrees Celsius.
For engineers that wish to upgrade or implement new PC-based control systems, it will be worthwhile to invest in the minimal effort required to retrofit the cabinet. However, for those simply desiring increased data acquisition and analysis on the edge, with no fundamental changes to the system architecture, industrial PCs offer a nearly plug-and-play solution with a wide variety of options to choose from to meet the applications needs.
Edge device certifications and software offer significant assistance
Examining these hardware, software and networking factors will lead engineers in the right direction, but they may encounter similar options. In these instances, examining product certifications and software capabilities can break a tie.
Depending on the cloud service in use, Microsoft Azure Certified IPCs or controllers approved by Amazon Web Services (AWS) can provide a better option and peace of mind. Controllers with multiple certifications could also reassure engineers that hardware changes will not be necessary if the company eventually decides to change cloud services.
Regardless, PC-based controllers are inherently well-suited to accommodate public and private cloud systems.
In addition, PC-based controllers should offer not only the best processing power for edge computing applications, but also use the best operating system. Engineers should ensure that any edge device supports Windows 10 IoT and possesses the capability to easily handle upgrades down the road.
After all, the goal of edge computing is to make continuous improvements far into the future. With the proper software and hardware selection, a successful edge computing implementation will boost machine performance, reduce downtime, increase throughput and ensure factories remain as efficient and competitive as possible. Carefully considering the many PC-based controller options will give controls engineers a serious edge.
Want to learn more about the benefits of PC-based control — and bust myths that legacy controls vendors use? Download the whitepaper about IPC advantages below.
Eric Reiner is the IPC Product Manager for Beckhoff Automation LLC.
A version of this article previously appeared in Control Engineering.