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Case Study: Methodical Approach to a Systems Upgrade


Case Study: Methodical Approach to a Systems Upgrade


ECS Solutions, Inc. (ECS) recently helped a client with an upgrade by leveraging ECS’ methodical approach to system solutions.  Their client has three very similar processing areas known as casting pits.  Each was controlled by an independent GE 9030 PLC system, each with a main, and each controlled by a local BLUE Open Studio HMI from ProFace America.

The 9030 PLCs that were installed were robust and accurate for these areas when originally installed.  Over a long period of time, the systems were maintained and augmented by several personnel from both inside and outside the organization.  The result, as is often the case in legacy automation systems, is system drawings that are littered with hand comments and sketches on paper drawings.  These systems also feature code that works…. until it doesn’t due to getting lost in a discarded section of logic that was thought to be disabled but was never removed.  These situations are often referred to as “ghosts” or “gremlins” in the code and they can be difficult to troubleshoot. Frequently, the solution is to reboot entire systems to exit from the offending area.

ECS’ methodical approach to systems upgrades was exactly what was required for the revised solution.  Their team worked onsite to reverse engineer the existing systems via interview of the client’s staff, review of the physical connections inside panels and the field, and detailed data code review.  From this investigation, they developed control narratives and plans for the eventual equipment installation.  ECS then retreated to their office to develop the revised solution.

The ECS team developed comprehensive drawings for six control panels, each system’s main PLC enclosure, and a remote I/O enclosure.  From there they built the new control panels and developed installation documentation.  Later, this documentation became the “connect the dots” instructions for the systems’ switchover.

New logic was developed for a series of new Rockwell Automation CompactLogix controllers.  The CompactLogix were each coupled with a new PanelView Plus 15” human-machine interface (HMI) screens.  Each casting pit was configured as a segmented Ethernet network with a new Rockwell Stratix switch in each main control panel providing communications between that area’s controller, its remote I/O rack, its HMI, and connections to the adjacent processing areas.

Most of the processing logic was straightforward once the code was reviewed and the system requirements identified.  The CompactLogix controllers’ processing power was utilized to create algorithms that the prior controller could not execute.  For example, the new controllers could handle predictive speed calculations that were based on multiple variables which were used during physical ramp-up, all of which converted to PID-based speed control using an encoder once each area’s casting table was moving.

It was a simple yet elegant solution that leveraged all the strengths of the Rockwell Automation platform in a powerful yet small form factor that fit the needs of the application both logically and physically.

The new control enclosures were delivered ready to install.  ECS provided staff to supervise installation and verify connections between the Christmas and New Year’s holidays with system changeover and runoff shortly after the second holiday.  In all, the system was installed quite efficiently thanks to the methodical investigation and simple-to-follow installation documentation that was provided by ECS.  The legacy 9030 systems served the client well for many years and the new CompactLogix solution should provide similar function with modern, enhanced capabilities for decades to come.

Perhaps most importantly, this satisfied ECS client has already engaged the team to continue their modernization efforts elsewhere in the plant and to investigate an area or facility-wide Ignition solution for enhanced supervisory control in the future.

Posted In: Case Studies, Metals Industry, PLCs