Modern switches expand Power over Ethernet applications
Author : Alan Bollard, Westermo UK
10 July 2023
How are the latest generation of PoE switches enabling power and data-hungry devices to be implemented within challenging industrial applications?
A new generation of Power over Ethernet (PoE) switches is helping to implement secure data communication networks, in industrial applications which incorporate devices that consume more power and transmit more data. This functionality is helping to simplify network design and installation, reduce costs, and expand the number of suitable applications.
PoE technology, which provides electric power over a single twisted-pair Ethernet cable, has been available since the early 2000s and is widely used for data networks supporting sensors, IP cameras, and wireless access points. Using only a single cable to deliver power and connectivity to a device creates a range of benefits, including reduced network complexity, cost savings, and the ability to create networks in remote locations with limited access to power.
In a traditional Ethernet network, an independent power supply, along with safety equipment, would be required for each device. Because local power is no longer required, PoE networks allow devices to be installed in remote locations that were previously difficult to access. Because PoE eliminates the need for devices to be tied to an electrical outlet, it enables much greater installation flexibility, allowing individual devices to be situated wherever they are needed.
As a result, PoE networks can be much simpler and more efficient. The use of a single cable for power and data means that installation costs are lower than those of traditional wiring. Reliability increases because there is less cabling exposed to environmental factors such as electromagnetic interference. In addition, with a single source of power for each end device, installation is simpler and less hazardous than when multiple adapters and outlets are required.
PoE also enables outdoor installations without the need for additional electrical infrastructure. Once again, this helps to reduce installation costs, but also allows for simple network expansion. Scalability is another key benefit, with easy network expansion possible without the need for additional on-site network design expertise. As a result, PoE networks can be scaled up easily, with new devices placed in additional locations, as and when required.
PoE and PoE+
One limitation of PoE is the amount of power that can be provided to devices across the network. Historically, PoE has had a limit of 15.4W, which makes it challenging to implement devices that consume more power, such as CCTV cameras, IP cameras and video IP phones. The introduction of the separate PoE+ standard has helped to ease this issue, allowing up to 30W to be provided and enabling devices with much higher power requirements to be deployed.
Power management is still very important. All devices on a PoE network are allocated a ‘power budget’, but if too much power is drawn by all the devices on the network at the same time, this can cause issues and limit functionality. To overcome these issues, PoE devices can prioritise which ports receive power. This is known as ‘PoE Priority’. Devices can be configured in terms of their importance, and classified as ‘low’, ‘high’ or ‘critical’ devices. Should the demand for power be too high, a PoE power sourcing device, such as a PoE switch, will reduce the power output to those devices configured as low and high. This ensures that critical devices are always supplied with power.
PoE switches
As with other Ethernet networks, switches are required to connect the various PoE devices together, and efficiently manage the flow of data between them. The PoE switches are also used to provide power to the connected devices. For industrial applications, there are PoE switches specifically designed to withstand extreme temperatures, humidity and electrical environments. Industrial switches are also vibration- and shock-resistant, making them ideal for harsh work environments, such as those found in railway trackside, marine, oil and gas, and mining.
Using the PoE switch as the power source allows for much simpler network expansion and installation. The latest PoE switches, such as Westermo’s Lynx PoE switches, support networks with greater power demands, capable of providing 30W of power via eight ports, for a combined total of 240W. This is more than enough power for many PoE installations.
Data management functionality has also been enhanced. In the past, PoE switches have been used mostly just to provide power to connected devices, but now they can manage modern data networks. Layer 2 and layer 3 functionality enables effective and efficient data management. PoE switches can now support a range of communication protocols and, of course, are able to meet the growing bandwidth demands, with gigabit speeds supporting applications such as HD IP CCTV cameras in industrial settings.
Network reliability and resiliency are essential. The possibility of ground loops, which can interfere with the data signal, can be an issue, but the latest switches incorporate galvanic isolation to provide an effective method of breaking ground loops. The latest PoE switches also provide redundant and fast failover connectivity, ensuring rapid recovery should a device or connection between devices be lost. This is enabling PoE networks to be used in mission-critical applications.
Ensuring the security of industrial data communication networks is of paramount importance, especially with cyberattacks becoming increasingly sophisticated. To reduce risk and increase cyber resilience, the latest PoE switches incorporate advanced cybersecurity features. These can be used to build networks in compliance with the IEC 62443 standard, which defines technical security requirements for data communication network components.
More information here.
Alan Bollard, Westermo UK
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