Using Gigabit Ethernet to build future-proof networks

With industrial network demands increasing, the transition to Gigabit Ethernet architectures is upon us.

Islands of automation are disappearing from the industrial landscape, as facilities, workstations, and individual devices that once functioned alone are being connected as organizations seek to integrate operations throughout multiple facilities and across the extended enterprise. These developments mean that industrial networks initially created to manage a process or provide basic monitoring capabilities have to do more, such as managing increased data flow from sensors and video monitoring systems, innovating processes with Machine-to-Machine (M2M) communications, or sharing data between facilities in real time to synchronize operations. The possibilities are limitless – but current network bandwidth is not.

Gigabit Ethernet (GbE) will provide the network backbone for future systems that rely more heavily on video, sensors, and applications that require faster, higher volume data sharing. While GbE clearly represents the future, GbE networks are not needed for many of the devices and processes running today, leaving many organizations wondering what their industrial networking migration strategy should be.

Industrial networking is concurrently in the middle of two transitions. First, Ethernet-based protocols continue to displace older fieldbus technologies. Flexibility is a major reason Ethernet has become so popular for networking in industrial and remote operations – EtherNet/IP, Modbus TCP/IP, PROFINET, DeviceNet, and other popular protocols are all Ethernet based. As these networks continue to grow, a second transition is underway to a next-generation Ethernet technology, Gigabit Ethernet (GbE).

Distinguishing Ethernet

Ethernet has become widely accepted and installed because of its speed, reliability, and support as an international standard. Today, industrial Ethernet networks typically use 10/100BASE-T “Fast Ethernet” technology with 100 Mbps bandwidth that can also support older 10 Mbps (10BASE-T) Ethernet devices.

Gigabit Ethernet is 1000BASE-TX. By definition, it provides 10 to 100 times the bandwidth of the 10/100 BASE-T networks and devices currently installed in many facilities. This bandwidth enables data to be transmitted more quickly, and also allows the network to carry larger data files (for example, higher resolution images) without experiencing Quality of Service (QoS) issues.

Gigabit Ethernet also has a lower switching latency than earlier generation technology, which may be more important than speed for industrial control operations. Switch latency refers to the time required for a packet to enter and exit a network switch. Reduced latency is a welcome development for highly sensitive motion control systems.

10BASE-T Ethernet and industrial protocols based on it are half duplex technology (meaning they can only send or receive at one time) and thus have a higher latency, which has proven to be an inhibitor when using devices that require a modern infrastructure. Gigabit Ethernet and Fast Ethernet are both full-duplex protocols, which means they can send and receive simultaneously.

Gigabit implications for industrial roadmaps

Forward and backward compatibility is one of the key advantages supported in the Ethernet standard family (IEEE 802.3). GbE, Fast Ethernet, and 10 Mbps Ethernet devices can all be used together on the same network. With proper planning, GbE will provide a seamless upgrade path while preserving previous investments in devices and network administration expertise.

Enterprises will likely need to support a mix of Fast Ethernet and GbE devices in the near future. Fast Ethernet provides outstanding performance for many industrial control and remote monitoring applications, and is the network connection built into many leading Human Machine Interfaces (HMIs), controllers, sensors, and other industrial automation equipment. However, these devices were developed to transmit limited data and may not be optimized to support the data, voice, and video traffic that typically flows over modern networks. Video transmitted over Fast Ethernet tends to be choppy, and the bandwidth is also insufficient for high-speed motion control and other applications that require minimal latency.

Because Fast Ethernet and GbE will co-exist, enterprises should develop a flexible network backbone that can readily support both technologies. Enterprises can achieve the flexibility to bridge current and future requirements by using network switches that support different protocols, media types, and modules. For example, Red Lion’s N-Tron series NT24k managed switches offer up to 24 ports that support a mix of GbE and Fast Ethernet, copper, and fiber, and are configurable to work with different protocols, network architectures, and modules.

Figure 1: The N-Tron series of managed Ethernet switches provides flexibility for variety of communications protocols and network architectures while supporting both Fast Ethernet and Gigabit Ethernet (GbE) technology.

Gigabit Ethernet applications

To date, most organizations have upgraded to GbE to some extent, either because they wanted to use more video or to future-proof their networks to accommodate more traffic and next-generation devices and applications. A few emerging applications follow:

Largely populated networks

All signs point to more connectivity in future field and factory operations. There have been numerous studies and forecasts predicting explosive growth for Machine-to-Machine (M2M) connectivity, the Internet of Things (IoT), and industrial networking. Industry leaders have predicted the number of networked devices will double to 50 billion between 2015 and 2020. Much of this increased connectivity will occur in the industrial space in the form of sensors and M2M devices, based on current automation trends and the high percentage of OEMs that are building M2M capabilities into product offerings.

Workstations that currently include a few devices connected to an HMI in an isolated ring network will likely evolve. Soon, a workstation may interface with dozens of sensors that support robotic production equipment, with each component reporting its status and production data to the cloud. Not only will there be more networked devices in the future, the devices will share more data and have more interactions with other systems. These developments underscore the need for network infrastructure that can support both GbE and older technology, while providing enough ports to support multiple devices.

Facility-to-facility connectivity

Industrial networks are links in a network of networks that make real-time data available throughout the extended enterprise. Remote cameras on wind turbines or oil wells may be monitored by a technician thousands of miles away. Data from sensors, Remote Terminal Units (RTUs), and other devices that are spread out over several acres at a manufacturing facility might continually report their status conditions to feed centralized production management and maintenance systems. In this scenario, Fast Ethernet or fieldbus protocols may be sufficient for devices at the local level, while GbE provides the network backbone for communicating with other buildings and remote locations.

Video cameras

Video is becoming increasingly important for facility management and production control operations. There is growing demand for traditional surveillance, but many new and powerful use cases are also emerging. For example, video cameras are being installed on wind turbines to enable remote inspection. If turbine performance changes suddenly or an alert is generated, a technician hundreds of miles away can use the camera to inspect the turbine for damage. This can save time and money by eliminating expensive field service calls. If on-site service is needed, technicians can use video footage to help diagnose the problem so they can bring the right tools and materials to fix the problem on the first visit.

Low-cost, closed-circuit surveillance cameras do not provide the image quality needed for remote monitoring or parts and assembly inspection. These applications require better quality images and a higher capacity network to carry them. Some surveillance systems use cameras that capture one Frame per Second (FPS), and most systems operate at 10 FPS or less. Conversely, machine vision cameras used for part identification and assembly verification may run at 48 FPS and have more megapixels to create higher-quality images. The combination of higher speed and higher quality results in inspection applications requiring much more bandwidth than traditional surveillance systems.

Surveillance applications can also benefit from Gigabit Ethernet GbE connectivity because it supports higher resolution images, better motion quality, and enables more cameras to be used without negatively impacting network performance. The number of cameras to be supported on the network is also an important consideration. For example, intelligent highway systems benefit from having input from more locations, but only if adding cameras will not slow the network. These requirements fully support the deployment of a GbE backbone.

Future needs: Flexible, modular solutions

As different parts of factories, wind farms, and upstream and downstream oil and gas facilities connect to each other and to the cloud, the islands of automation that marked earlier-generation industrial automation systems will disappear. They will eventually be replaced by networked environments that enable enterprises to connect, monitor, and control their assets remotely. These changes won’t occur all at once, so enterprises will need to support current systems while building for the future. The components to create the connected enterprise are available now, and the evolution can take place as quickly as network bandwidth allows. Gigabit Ethernet is the bridge that enterprises can use to build networks today to pave the way to bring more video, sensors, M2M, and other connected devices into their operations tomorrow.

Diane Davis is Director of Product Management, Networking at Red Lion Controls.

Red Lion Controls