Correcting Control Network Communications

Reliability is a broad topic for process manufacturers. It encompasses plant equipment, the production process, reliability-centered maintenance (RCM) programs, overall equipment effectiveness (OEE)—just to name a few.

We’ve touched on many of these areas in prior posts and will again in the future. I caught up with Emerson’s Melinda Hull who shared several reliability-related presentations that will be presented at the Emerson Exchange conference, taking place in the Dallas, Texas area September 30-October 4.

One such presentation centers on control system networks. The presentation, Your Control Network is Critical – or is it Critically ILL?, features engineers from a Latin American paper producer and Emerson’s Francisco Navarro. In their abstract they note, “Trivial network anomalies can gravitate towards a network cancer.”

The site was experiencing extensive network issues causing switchovers between the redundant control networks. These switchovers were occurring on the order of 100,000 times per day. The overall non-responsiveness of the control system applications was also very evident. Clearly, the anomalies had metastasized. Unfortunately, this degraded state of system communications resulted in an unplanned unit shutdown.

Control Room InteractionsFrancisco is a member of the Lifecycle Services team and was called in to perform a Network Assessment service. With this structure service, Francisco helped the mill staff identify network hardware and configuration issues and recommended actions based on Emerson’s network installation guidelines, best practices, and industry standards.

Among the issues discovered during the network assessment activity were incorrect port configurations, and improper or missing grounding connection for the switches. It was also found that the network architecture was not equipped with the current supported network hardware that therefore required specific configurations for the control system.

With the Network Assessment service, Francisco worked with the mill staff to gauge the integrity of the network and perform a complete benchmark for system communications. The network integrity was in a highly degraded state, which impacted overall system communications. The team performed several corrections to the existing configuration to resolve the continuing network anomalies.

The network issues causing the control network switchovers were resolved and reliability returned to the production process. As part of this service, a Network Assessment report, documenting all the findings and recommendations made, was provided to the mill technical staff, which can be used as reference to help avoid future control network issues. No network-related anomalies have disrupted the site since the network issues were identified and corrected.

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