While it’s true that much of the consumer- and office-grade network equipment will work with work for Industrial Ethernet, the question is, for how long? Research shows that the most common cause of Industrial Ethernet failures is cabling and connectors.
Industrial Ethernet and commercial Ethernet aren’t exactly the same. They differ in how they send and receive information, the topologies deployed, the components and the testing considerations. In fact, more than half of Industrial Ethernet problems can be traced to cabling, which requires a shift in thinking when testing and troubleshooting. While it’s true that much of the consumer- and office-grade network equipment will work with work for Industrial Ethernet, the question is, for how long? Research shows that the most common cause of Industrial Ethernet failures is cabling and connectors. Understanding how Industrial Ethernet connectors, cables and network gear differ from their office-grade counterparts is one secret to keeping an industrial network running.
Non-industrial gear isn’t ready for the vibration, moisture, electrical interference, chemicals, and more that you’ll find in a plant. Smart people realize this, but sometimes they use suboptimal gear for a quick fix to get operations back up and running. Since quick fixes are often forgotten, it’s best to avoid using non-industrial gear for your Industrial Ethernet. As we highlighted in a previous blog, connectors used for Industrial Ethernet are also different in that they need to withstand harsher mechanical factors, the potential for ingress, extreme temperatures, chemicals and electromagnetic interference. Therefore, we often see M12 and M8 locking thread connectors used because they are far more durable and better designed to handle ongoing vibration compared to commercial Ethernet RJ-45 connectors. Cables too need to be able to stand up to harsher environments, so you want ones that feature jacket materials with higher tensile strength and chemical resistance, as well as higher strand counts for flexibility. Both connectors and cables need to meet more stringent M.I.C.E. parameters used for classifying components in an industrial network where M is mechanical (flex, vibration), I is Ingress (moisture), C is Climatic (temperature), E is Electromagnetic (noise). MICE standards apply to any industrial Ethernet protocol, including EtherNet/IP, ProfiNET, EtherCAT, Modbus-TCP and others. Ethernet switches themselves also need to withstand wider temperature ranges, shock, vibration, etc., and they are often housed in industrial steel enclosures using DIN-rail mounting. They also require superior reliability and redundancy. While a commercial-grade Ethernet switch typically has a single power supply, Industrial Ethernet switches almost always have redundant power.
More than half of Industrial Ethernet problems can be traced to cabling, and the harsher industrial environment can require a shift in what you need to look for when testing and troubleshooting. For example, Industrial Ethernet cables can experience continuity problems caused by flexing, vibration, corrosion, and temperature changes. While continuity testing will find open connections, finding a poor connection requires measuring the resistance of each individual conductor. This can be done by testing for DC Resistance Unbalance with your Fluke Networks’ DSX CableAnalyzer series tester, which looks at the difference in resistance between each conductor of a pair. If too high, it could indicate a poor connection. Electromagnet interference (EMI)—the “E” in M.I.C.E.—can also damage Industrial Ethernet packets. To determine if a cable is susceptible to EMI, the DSX CableAnalyzer tests for Transverse Conversion Loss (TCL) and Equal Level Transverse Conversion Transfer Loss (ELTCTL), which are covered in both TIA and ISO M.I.C.E. standards. When testing, limits to M.I.C.E. standards can be selected in your tester to match the ‘E’ level of the environments—E1 for commercial office environments, E3 for environments close to powerful EMI sources and E2 for cable runs between E1 and E3 zones.
If you’re company has purchased office-grade connectors, cables or network gear in the past, a small investment allows you to quickly pinpoint and repair any problems that arise. Having a cable tester—even a basic one—enables you to determine if the cabling is at fault and where the problem is. And, having a tester with the right interface and test setup can save time. In industrial deployments, it is common to see cables terminated with M12 type connectors in a point-to-point configuration without cross-connections or interconnects. This essentially makes them just one long patch cord. Since channel testing does not include the performance of the plugs at either ends, the ISO/IEC 11801-3 standard added end-to-end (E2E) test limits. These can be performed using DSX M12D or M12X Adapters available with the DSX CableAnalyzer series testers. It is common to see some of these point-to-point links terminated to an M12 style connector on one end and an RJ45 style plug on the other. In this instance, you’ll need an M12 Adapter on one end and a Patch Cord Adapter on the other, since that’s what is used to test the performance of the field-terminated RJ45 plug.
This article was adapted from a blog post by Fluke Networks, worldwide leader in certification, troubleshooting, and installation tools for professionals who install and maintain critical network cabling infrastructure.
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