Maximize efficiency and flexibility with industrial PoE switches in automation

Abstract

Industrial automation is a complex and rapidly evolving field that requires robust and versatile networking solutions. One technology that has become a key enabler of automation is Power over Ethernet (PoE), which combines power and data transmission over a single Ethernet cable. In this blog post, we’ll look at how industrial PoE switches can maximize efficiency and flexibility in automation by simplifying cabling, reducing installation time, and centralizing management.

PoE in industrial automation

The PoE standard was first approved by the Institute of Electrical and Electronics Engineers (IEEE) more than 20 years ago. That standard, known as IEEE 802.3af, allows for up to 15.4 watts of DC power per port. Since then, the IEEE has issued updated standards. The latest is IEEE 802.3bt Type 4, also known as 4-pair PoE (4PPoE) or PoE++. IEEE 802.3bt can deliver up to 90 watts of power per port to a range of devices, such as PTZ IP cameras, gas analyzers, video monitors, and embedded computers that require more power.


PoE has quickly gained popularity in the industrial sector for a variety of reasons, as it has in enterprise and commercial networks. First, it significantly reduces infrastructure complexity, especially in remote locations or areas of a plant where electrical outlets are not available. There is no need for an electrician to install or maintain PoE cable because of the low voltages involved, and installation does not require long runs of steel conduit or grounding enclosures, reducing initial implementation costs. Another advantage of PoE is that it gives network managers the ability to centrally monitor a device’s PoE power usage and other energy-related data. Non-essential devices monitored by a managed PoE switch can have their power automatically reduced or completely turned off when not in use. Flexibility is another advantage. Network devices can be installed in previously inaccessible locations because electrical outlets no longer restrict their placement. Replacing existing devices on the network requires more than just connecting the device’s Ethernet cable to a PoE network switch port. Additionally, PoE is standards-based, which ensures interoperability between vendors.


One area of ​​automation where PoE can provide benefits is the SCADA (Supervisory Control and Data Acquisition) network. SCADA is a way to remotely monitor and control equipment in automation processes in industries such as oil and gas production, distribution, utility power, and wastewater management.


One of the biggest changes in SCADA technology was its evolution from serial network protocols to the Internet Protocol (IP). The adoption of IP meant that hardware costs were lower and throughput could scale to 10 Gbps for end stations and 100 Gbps for backbones. It also meant that a SCADA network that deploys Ethernet as the access network could benefit from PoE. An array of PLCs, RTUs, sensors, and other SCADA end devices could be powered simply by connecting a device cable to an open switch port.

Industrial safety

While PoE is often praised for its flexibility and infrastructure savings, it also contributes to industrial security.


It is not uncommon for electrical systems powering industrial facilities to be 480V or 600V, which is more than enough to injure a worker from electric shock, arc flash, explosion, or other hazards. Low-voltage PoE reduces or eliminates the risk of short circuits, exposed wires, or accidental contact with live voltage. Overload protection, which protects against high power consumption and subsequent damage to devices or cables, is also built into PoE devices. If an overload is detected, power distribution is reduced or shut down to protect or repair connected equipment and reduce the risk of overheating or fire.


Is electrical safety important in automation projects? The overwhelming answer is yes. According to the National Fire Protection Association (NFPA), electrical accidents in the workplace cause thousands of injuries each year and almost one death per day.

Choosing a Network Switch with PoE Management

Network architecture, capacity, and scalability must be carefully considered when designing an industrial automation network that can accommodate PoE devices. This will require configuring several managed PoE switches to ensure reliable and efficient network operation. So what should you look for in a managed PoE switch?

Reinforced equipment

Switch operation is exposed to a variety of hazards, including electrical noise, humidity, harsh chemicals, vibration, and extreme temperatures. To mitigate or reduce these hazards, make sure you purchase industrial PoE switches with rugged, environmentally sound packaging with an appropriate Ingress Protection (IP) rating. Although less common, another hazard is the presence of classified areas in the facility where volatile, flammable liquids or gases are handled, processed, or used. In these environments, an explosion-proof switch will be required according to Class 1 Div 2 and ATEX codes.

Bandwidth requirements

Switch bandwidth determines the network capacity, affecting the speed and reliability of data transmission. Insufficient switch bandwidth can lead to network congestion, latency, and compromised device functionality. Whether a 10/100, 2.5G, Gigabit, or 10G switch is necessary depends on your application. It is also a good strategy to plan for additional bandwidth in case your needs increase in the future.

Power requirements

Make sure that the overall power budget of the industrial PoE switch can support all devices simultaneously, taking into account the power consumption of each device. Industrial networking devices, including optical sensors, access points, network lighting, and IP cameras, have a wide range of power requirements, typically ranging from 15 to 100 watts. Make sure that the industrial PoE switches have sufficient PoE power and power budget to support your devices. You must also consider that the maximum distance for PoE is 100 meters (328 feet) and that power loss can occur over longer distances. If this is the case, you will need to install additional network infrastructure, such as intermediate switches, PoE extenders, or power injectors.

Configuration and port types

The number of PoE ports required on a switch depends on the number of PDs you plan to power, although it is good practice to have more to allow for expansion. The number of ports and the PoE standard will significantly affect the quality, scalability, and flexibility of your network. Having a mix of Gigabit and Fast Ethernet ports allows you to support devices with different bandwidth requirements.

Compatibility

Before power can be transmitted, the industrial PoE switch and the powered device must negotiate to determine the device’s power requirements. The outcome of the negotiation determines whether the two are compatible and whether the device can safely obtain the power it needs. If the negotiation is successful, the powered device will not receive too much or too little power; both conditions can damage the device or cause it to fail.

Security features

Having advanced security features in an industrial PoE switch, such as port security and access control lists (ACLs), is essential to protecting networks in the face of growing cybersecurity concerns

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