SOLUTIONS IT AND OT INFORMATION NETWORKS By Mark Mullins
Tools troubleshoot industrial Ethernet problems Technology ranges from the simple to the sophisticated
D
ue to its inherent reliability, performance and interoperability, Ethernet has rapidly become the communication protocol of choice for automation and control systems in the industrial environment. In fact, recent surveys found that 70% of all newly installed factory automation nodes employ Industrial Ethernet. This includes Industrial Ethernet applications like Modbus TCP/IP, EtherCat, EtherNet/ IP and Profinet encapsulated with Ethernet frames to send and receive supervisory and control information between industrial devices and systems. All of these applications are designed to work over Ethernet-based twisted-pair copper or fiber cables and connectors that have been hardened to stand up to factors such as vibration, dust and liquid ingress, chemicals and electromagnetic interference found in the industrial environment. The ability to maintain operations and productivity via Industrial Ethernet is only as good as this underlying cabling infrastructure, but even after that infrastructure has been installed, tested and apparently doing its job, problems can arise that bring industrial operations to a screeching halt. Whether caused by accidental damage and contaminants to cables and connectors in the harsh industrial environment, interference from new machinery, or changes to infrastruc-
ture that went awry due to the wrong components or improper installation, plant managers and operations technology (OT) staff need to act fast to locate and fix the problem to keep machines in production. With more than half of Industrial Ethernet problems traced to the cabling infrastructure, knowing the most effective way to troubleshoot can mean the difference between an hour of unplanned downtime versus days that could wreak havoc on production standards and translate into millions of dollars of lost revenue. The good news is that there are plenty of simple, inexpensive troubleshooting tools available that can help you quickly identify and locate copper and fiber cabling problems to expedite repair and reduce costly unplanned downtime.
Simple tools, simple problems
When machinery shuts down because it isn’t receiving Industrial Ethernet control signals over the cabling, the problem could be something as simple as a lack of continuity caused by a cut or break in the cable or a bad termination at the connecting interface. Checking for continuity is easily accomplished with wiremap testing that looks for potential problems like opens caused by broken conductors, shorts from improperly terminated or damaged connectors, or miswirings that result in reversed pairs, cross pairs or split pairs, where conductors within the cabling have been terminated to the wrong pin position at a connector interface. Rather than bringing in outside help with expensive testing equipment, you can use a simple, low-cost wiremap tool to quickly identify the problem. A good wiremapper will also indicate which pair is causing the problem, as well as verify the integrity of the shield on the cable — which is ideal for industrial environments where shielded twisted-pair cabling is the norm.
Figure 1: The ability to maintain operations via Industrial Ethernet is only as good as this underlying cabling infrastructure, but even after being installed, tested and apparently doing its job, problems can arise. Courtesy Fluke
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• April 2021
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