Edge computing for efficiency, quality

Edge devices streamline operations and offer many benefits including enhanced efficiencies and quality of service for industrial manufacturers.

By Nate Kay, P.E. February 26, 2019

Edge computing refers to the edge of network computing, but what network? In industrial manufacturing, many control systems are set up on local Ethernet networks. These networks may consist of a local business network, industrial computers, programmable logic controllers (PLCs), and industrial touch screens often called human-machine interfaces (HMIs). Many benefits derive from connecting local networks to larger public networks or server computers.

For simplicity’s sake, publicly-accessible networks will be referred to as the cloud. The edge is the boundary between these local networks and the cloud. Edge devices provide the interface between the cloud and the local networks.

An airport is similar to how edge devices and the cloud interact. The hub is the central airport, often located in larger cities, where flights are routed through. The spokes are the routes planes take in and out of the hub airport. Smaller cities have connecting flights to hub airports. If, for example, someone is traveling from Columbus, Ohio, in the United States to the United Kingdom, they may first fly from Columbus to an airline hub in Chicago, then to a hub in London, and finally to their destination city. Think of the cloud as the hubs and the edge devices as the smaller local airports.

Benefits of edge devices

The first benefit cited in the airport analogy was a reduction in traffic over a point-to-point model. Likewise, when it comes to the Internet of Things (IoT), instead of having individual devices connect point-to-point to the cloud or each other, these devices connect to an edge device, which then connects to the cloud. Edge devices can reduce the overall volume of data that must be transmitted and act as a buffer, which helps improve efficiency and quality of service (QoS).

Many existing networks are not setup to connect directly to the cloud. The network architecture, including information technology (IT) standards such as domains, domain name system (DNS), dynamic host configuration protocol (DHCP), firewalls, etc., isn’t there. Redesigning the local network from the ground up can often be time-consuming and cost prohibitive.

However, adding an edge device can allow existing networks to connect to the cloud without overhauling the network. Edge devices incorporate IT practices such as firewalls, transport layer security (TLS)/secure sockets layer (SSL) security protocols, and network address translation (NAT). This allows existing devices (including PLCs and HMIs) to exchange data with the cloud through the edge device while the edge device provides isolation and security between the cloud and the existing network.

Computing resources

Another advantage of edge computing is some computational resources can be handled by the edge device instead of in the cloud or by the local control system. For example, consider an industrial controls application where data collection and analysis is needed. The existing control system may not have devices with the capability to collect and analyze large amounts of data. Even if it did, its main function is not data collection and analytics, but to keep manufacturing processes running.

The cloud-based system has plenty to do, including serving up the data, providing reports, and handling the requests of dozens of other control systems and end users. By having the edge devices handle some of the data collection, buffering, and analytics we can reduce the burden on the cloud-based system and the control system can perform its critical tasks.

There are several edge devices that allow users to connect existing control systems to the cloud. Some of them allow the user to connect the existing control system to cloud-based systems with little-to-no modification of the existing devices and network. This is possible by selecting edge devices that incorporate technology such as NAT, virtual private networks (VPNs), firewalls, Layer 2 switching, and Layer 3 routing.

Edge devices can provide an efficient and easy way to move today’s technology into the future with a well-established hub and spoke model.

Nate Kay is a project manager at MartinCSI. Edited by Emily Guenther, associate content manager, Control Engineering, CFE Media, eguenther@cfemedia.com.


KEYWORDS: Edge computing

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Author Bio: Nate Kay is a senior project engineer at MartinCSI.