Bench Talk

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Across manufacturing facilities and infrastructure, Ethernet-connected devices have become increasingly common. As networks expand to support more connected equipment, the need to deliver both data and power to distributed endpoints continues to grow. Running separate power and data cables to each device can increase installation time, material cost, routing complexity, and maintenance requirements. Power over Ethernet (PoE) simplifies the connection by delivering power and data over the same Ethernet cable. In existing networks, PoE injectors provide another benefit by enabling PoE functionality without needing to replace non-PoE switches. This blog examines the deployment challenges facing industrial Ethernet networks, as well as the changing connectivity needs in these environments and how PoE injectors can support network modernization.

The Deployment Challenge Behind Industrial PoE

Separating power and data cabling complicates industrial network deployments because each additional cable must be routed, installed, and maintained. This increases installation time and the amount of infrastructure surrounding the connected equipment. As networks expand, those additional runs can add material and deployment costs and make future changes to physical layouts more difficult. Using a single Ethernet cable for both power and data can reduce the cabling burden and simplify connections to distributed devices (Figure 1).

Figure 1: A legacy security camera network requires separate connections for power and data to each camera. (Source: Author)

For existing equipment in these facilities, many industrial networks already rely on Ethernet switches that do not provide PoE. Replacing those switches solely to add power delivery can increase cost and disrupt upgrades. PoE injectors offer an alternative by supplying power to the Ethernet connection between an existing non-PoE switch and a PoE-capable device, enabling designers to add power while continuing to use much of the existing network infrastructure. This solution also gives them more flexibility when equipment is added or relocated.

Modernization is not only about adding connections, though. Industrial networking equipment often operates in environments where extreme heat or cold, moisture, dust, and vibration can affect long-term reliability. PoE connections must maintain reliable power and data transmission under harsh operating conditions, often without active cooling and instead relying on passive heat sinks and rugged enclosures. Features such as surge protection and electrical isolation can help protect equipment from electrical disturbances, while diagnostic functions give maintenance teams greater insight into conditions along the connection.

Why Industrial Networks Are Moving Toward Simplified Edge Connectivity

Diagnostic visibility into network conditions becomes even more important as industrial networks expand and integrate more connected devices. Low latency and dependable connectivity are essential for enabling data filtering and processing at the edge rather than in the cloud. Real-time monitoring and predictive maintenance at the edge are crucial to initiating timely automated responses to potential safety concerns and technical malfunctions.

Networked machines and equipment in manufacturing facilities can exchange sensor and status data across an automated production process in which data collected and analyzed by a sensor on one machine can inform the response of another machine along the production path. Similarly, networked infrastructure such as traffic control systems can use information collected from distributed cameras and sensors to inform decisions elsewhere in the system.

As the networks become more connected, they must also meet higher expectations for uptime and maintainability. Simplifying edge connectivity can make it easier to add or relocate devices while limiting changes to existing infrastructure. PoE injectors are one way to extend edge connectivity without requiring otherwise functional non-PoE switches to be replaced.

Applying PoE Injectors in Existing Industrial Ethernet Networks

By using twisted-pair network cabling, PoE injectors enable data and low-voltage direct current to be delivered simultaneously over a single transmission path. These injectors’ ability to be implemented in conjunction with non-PoE switches helps avoid costly and time-consuming replacement of pre-existing equipment. Single-cable power and data delivery to edge devices in production environments and infrastructure significantly reduces the number of cables and connections required to operate those devices and provides designers with greater flexibility both during the initial design phase and when relocating equipment or integrating additional devices later (Figure 2).

Figure 2: A PoE injector adds power to data from an existing non-PoE Ethernet switch, enabling power and data to be delivered over a single cable to connected devices. (Source: Author)

While simplifying the connection is important in an industrial environment, the equipment must also be protected from electrical conditions that could disrupt communication or damage connected devices.

A key protection feature of PoE injectors is surge protection against transient overvoltage that can result in port failures and device burnout. Surge protection is a critical factor in outdoor applications that may be exposed to lightning or buildings with separate or poor grounding. Another essential form of protection comes from electrical and galvanic isolation that prevents ground loops and low-frequency noise, reducing the potential for damage to connected devices.

Industrial PoE systems can also provide more visibility into potential problems. Shield-current monitoring provides diagnostic data to help identify potential grounding issues during implementation and to support predictive maintenance by revealing conditions that may lead to equipment failures or malfunctions, thereby extending equipment lifetimes and reducing maintenance and costly network downtime.

For industrial and infrastructure applications, Phoenix Contact's PoE injector portfolio delivers power and data over a single cable while incorporating these protection and diagnostic features. The injectors provide integrated surge protection, galvanic isolation, and shield-current monitoring to protect against potential short circuits and shield currents resulting from potential differences between network and device grounds, as well as electromagnetic compatibility (EMC) interference. The Phoenix Contact PoE injectors also support multiple connection technologies for design flexibility and can add PoE capability to Ethernet links from existing non-PoE switches.

Conclusion

Implementing PoE injectors in existing networks can modernize power and data delivery without a complete system overhaul. By reducing the number of cables and field connections required, designers can create simpler installations with greater flexibility for compatible powered devices. Integrated surge protection, electrical isolation, and shield-current indication can improve protection and make certain field-wiring problems easier to identify during commissioning and maintenance. Together, these capabilities provide a practical way to expand industrial networks with additional connected devices while avoiding the cost, complexity, and downtime associated with extensive recabling and system-wide retrofits.

Author

Alex Pluemer is a senior technical writer for Wavefront Marketing specializing in advanced electronics, emerging technologies and responsible technology development.