Building and Installing a Reliable Industrial Ethernet Infrastructure

In the oil, gas and petroleum processing industries, an integrated, environmentally hardened communications infrastructure is essential to high network performance, reliability and uptime. Here are six basic factors to consider in designing a communications network infrastructure for use in extreme conditions.

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With industrial Ethernet becoming the preferred data communications infrastructure for mission-critical industrial automation and control, the challenge is to design a system made to withstand extreme and often hazardous environmental conditions.

Built on the same standards-based networking platform as enterprise Ethernet (Ethernet LAN standard IEEE 802.3), industrial Ethernet provides secure and seamless interoperability when connecting the plant to the central administration office and the Internet. As a result, more companies in the oil, gas and petroleum-related industries are looking to leverage the capabilities of Ethernet communications across all their operations.

Perhaps no other industry group faces the type of harsh conditions that can threaten the performance of communication system components. Whether installed in an oil or natural gas exploration site, extraction operation, processing plant or refinery, the signal transmission must be tough enough to withstand the destructive effects of temperature extremes, moisture, humidity, dust, mud, oil, solvents and potentially corrosive chemicals. The network’s sensitive electronics may also be exposed to sunlight, electromagnetic interference (EMI), and the ever-present danger of fire and explosion.    

Here are six practical guidelines oil, gas and petroleum plants should consider in planning, building and installing a data communications network rugged enough to stand up to the environmental rigors and hazards to which it is exposed.

1.   Calculate the real cost of downtime.  Analysts report that a large percentage of unplanned downtime in industrial operations can be attributed to network infrastructure failure. In fact, as many as 72 percent of network faults can be attributed to failure at the OSI (Open Systems Interconnection) Layer 1 (Physical Media), Layer 2 (Data Link) and/or Layer 3 (Network).  

In mission-critical operations, downtime is not an option. If a switch, connector or cabling system should fail, the cost of parts replacement and repair represents only a tiny fraction of the overall costs associated with downtime.  The indirect costs of Ethernet system failure include lost productivity, delayed processes, cost of system shut-down and start-up, possible lapses in security and safety, and the loss of service to customers relying on the plant’s mission-critical output. These indirect effects can send total downtime costs soaring to hundreds of thousands, even millions of dollars.

2. Be sure to specify industrial-grade network components.  In office settings, the Ethernet infrastructure is typically installed in a clean, quiet setting in which cables, hardware and connectivity components are fully protected.  Industrial facilities present a starkly different reality. Here, many network components reside in harsh environments which even well-made commercial off-the-shelf (COTS) Ethernet systems cannot withstand. Sunlight, moisture, dirt and other contaminants can all degrade the cables’ physical integrity and electrical performance, resulting in intermittent outages or even total system shutdown. Only field proven, industrial-grade components offer the rugged construction and durability required to provide optimal performance over a long service life.

3. Choose standard-based cables and connectivity components to fit each application. Industrial-grade cables that conform to the Ethernet LAN.IEEE 802.3 standard are made to resist the effects of sunlight, volatile temperatures, moisture and chemicals. They operate effectively in a wider temperature range (-40oC to +85oC) than commercial cables (0oC to +60oC).

Depending on the application within the plant, some industrial Ethernet products to look for include:
•    Heavy-duty, all dielectric, indoor/outdoor-rated optical fiber cabling in single-mode and multimode constructions. Many feature water-blocking agents for added protection in moisture-laden environments.
•    Industrial grade Cat 5e and Cat 6 cables with heavy-duty oil- and UV-resistant jackets. Some Category cables feature a Bonded-Pair inner construction in which the conductor insulation of the pairs is affixed along their longitudinal axis to ensure consistent conductor concentricity to prevent any performance-robbing gaps between the conductor pairs during installation and use.
•    Upjacketed and armored cables add extra protection in more extreme environments.
•    Continuous flex cables designed for use with continuous motion machines and automation systems.
•    Low smoke zero halogen (LSZH) cables, waterblocked and burial cables are also available.
•    Cables designed for use with leading industrial automation networking and communications protocols, such as EtherNet/IP (ODVA), Modbus TCP/IP, ProfiNet and Fieldbus HSE.
•    Industrial-grade connectivity components, such as: IP67- or IP20-rated UTP or FTP patch cords, connectors, modular jacks and plug kits, adaptors, faceplates and surface mount boxes.
•    Industrial-grade Cat 5e RJ45 and Micro (M12) cordsets and patch cords, including high flex versions

4. Select ruggedized switches, active network devices and accessories. A wide range of hardware is available to enable management of industrial Ethernet networks at the information, control and device levels. There are products to support both copper and optical fiber media, as well as switches capable of data speeds as high as 10 Gigabits per second.  At a minimum, all of these components – switches, connectors, and other hardware – should offer robust construction and resistance to high temperatures, vibration and EMI.

Typical COTS hardware is designed to operate from 0oC to +40oC, while industrial-grade Ethernet hardware operates efficiently from 0oC to +60oC – extendable to -40oC to +85oC (a conformal coating is also available for humid/moist applications). Also, excessive moisture and corrosive chemicals can inflict serious damage to the electronics in commercial switches, whereas ruggedized industrial switches are securely sealed to prevent ingress of these substances.

Industrial Ethernet hardware components include:
•    Hardened managed and unmanaged switches which come in a variety of copper/fiber port configurations, port densities, industry approvals and mounting options.
•    Firewalls to secure and isolate a network while still permitting authorized data communications to pass through.  Firewalls with VPN capabilities also allow secure, encrypted communication from a remote location through the Internet.
•    Wireless Access Points, Clients and Bridges in either DIN rail mount or IP67 enclosure-less housings now also support the faster, more secure and noise-immune 802.11n standard.
•    Related accessories such as hardened power supplies, SFP fiber transceivers and even software that provides network status, alerts and control from the automation network’s software or PLC.

5. Be sure to build in power source and data path redundancy. Sometimes overlooked in selecting industrial Ethernet switches are two kinds of redundancy essential to maintaining uninterrupted signal transmission and maximum uptime.
•    Power source redundancy means having an uninterruptible power source (UPS) to provide consistent and reliable switch performance. Specifying switches that have dual power input capabilities means that if one power source fails, the other immediately takes over.  
•    Data path redundancy provides an alternative path for data to travel in the event that any link between switches fails, threatening to bring the system down. This is the inherent flaw in the daisy-chain network topologies used by many industrial plants to connect automated machinery and devices.

Well-qualified industrial network system designers and integrators are knowledgeable about the best ways to create redundant power and data paths within the Ethernet topology.

6. Look for end-to-end integration to ensure seamless interoperability. In selecting industrial Ethernet components, it’s important to take the time to evaluate the market and select a qualified supplier capable of providing a top-quality, end-to-end Ethernet framework tailored to the application and environmental conditions.  Taking a “total system” approach eliminates issues of interoperability, ensuring that all components are seamlessly integrated and fine-tuned to deliver consistently reliable performance day after day, year after year.  And that, of course, is a primary objective for owners and managers of oil, gas and petroleum plants looking to install a high performing industrial Ethernet network.
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