By Paul Miller, Contributing Editor
The proliferation of standard Ethernet on the plant and factory floor, makes it clear that many of these industrial networks are not being monitored adequately. Thats because the people on the floor dont always have the right tools and because corporate network support people have different priorities.
Without effective monitoring capabilities in place, plant or factory personnel dont learn about impending problems or network events until after they occur. All too often, this is right in the middle of the night when outside support is not available. The right network monitoring tools can help plant-level people to determine quickly whether a problem is in the network or in a machine, controller or other network-connect device. With this information in hand, they can identify, locate and resolve many problems before the corporate network support people finish their first morning lattés.
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Paul Sperling, technical systems manager for the food products manufacturing division of Kroger (thekrogerco.com) in Cincinnati, has worked on both sides of the IT fence. When you have enterprise tools, there generally are politics involved with who can do what with the software, says Sperling. Its easier to provide the people on the plant floor with intuitive tools that dont get in the way of what needs to be done.
In many industrial plants, the people most responsible for quickly fixing the automation network if something goes wrong in the middle of the night are not all that well-versed in IT. They need tools that will help them quickly find the problem using a familiar industrial software interface, comments Troy Watts, automation technology manager at the Encompass Group (encompassgroup.ca), a Vancouver, B.C.-based system integrator. Enterprise-level packages work fine in larger plants where there is enough resident talent, but its likely that these will be beyond the scope of the average plant.
Without some type of network management, it can be difficult to diagnose automation system performance issues. For example, there could be a periodic high traffic load, due to something like a data backup for servers, that impacts system performance, states Dan Knight, marketing manager at Cisco Systems (cisco.com). With no way to monitor the network and correlate trends and events, it could be very difficult to understand the causes of these types of issues. Spending time and resources trying to diagnose problems without the proper tools can be very expensive in an environment with high cost of downtime or performance issues.
Clearly, theres no shortage of products being offered. IBM, Cisco, Computer Associates, Hewlett-Packard, Microsoft, Sun Microsystems, Juniper Networks and other well-known companies offer network management software and solutions. Most of these are enterprise solutions designed for large, complex corporate networks. As a result, theyre typically very expensive and require a high degree of IT expertise to use effectively. These solutions are not well-accepted by overburdened engineering, maintenance and operations staffs at the factory level.
The IT tools that are out there are too complicated for use at the plant floor level by plant engineers and operators, says Mark Fondl, president and CEO of Network Vision (intravue.net), Newburyport, Mass. (Figure 1) They need tools that enable them to solve problems at the plant floor level quickly and easily. This helps them understand the network better so that they can communicate more effectively with the IT guys.
This software automatically discovers all the devices on the network and then maps their connections.
We embedded its N-View into existing RSView and Wonderware HMIs so the plant guys are using their existing screens, says Watts. Weve animated the screens to show the state of the network and put in alarms to indicate hardware, traffic or media issues. This provides a point of reference so that the plant people can start fixing things before they get out of hand and determine the root cause of recurring problems. When we started using this product, it was the only solution that offered OPC to let us plug into HMIs without having to expose users to yet another piece of software.
While its often assumed that lower-cost, unmanaged switches cant be remotely monitored or diagnosed, N-View software claims a unique solution for that. Switches equipped with the appropriate firmware periodically autocast a small Ethernet packet containing port-by-port switch status. An OPC server captures the data, and the variables can be displayed as string variables in most HMI applications with OPC client capability. This provides remote network traffic, status and error monitoring for N-Tron unmanaged switches with real-time data visibility within familiar plant applications. Both the software and OPC server are included at no charge with the switches.