Water/Wastewater Operators Rely on Tesco Control’s Proven Automation Migration Experience
In these examples, Tesco Controls demonstrates the multi-discipline experience necessary for migrating water/wastewater legacy automation to modern platforms.
Raju Nair, the PLC Applications Engineering manager at Tesco Controls, wrote an article recently published in the December 2020 edition of Control Engineering’s Global System Integrator Report. CFE Media, which publishes Control Engineering, has ranked Tesco at number 10 among the “2021 System Integrator Giants”, up from number 14 in 2020.
Raju’s article is titled Migrating Legacy PLC Programs to Modern PLC Hardware , and it presents Tesco’s expertise in migrating legacy automation systems to modern hardware and software platforms, while avoiding unacceptable downtime and reducing risk. Following is a summary, or you can click the link above for the full text.
Aging Systems Introduce Challenges
Water/wastewater operators must carefully manage their maintenance budgets, often keeping systems running well past obsolescence. Even traditional hardwired controls need to be upgraded eventually, but this became more apparent and, in some ways, more burdensome as automation transitioned to more capable digital systems like programmable logic controllers.
For many users, PLCs become mysterious boxes which run well for long periods of time, and so they are largely ignored. Over the years, updates are often not documented, there may be no backups, and perhaps the team loses the hardware, software, and/or skills needed to upload, download, or troubleshoot the code. When factory support and parts availability come to an end, a migration or upgrade is needed.
Migration Planning
At some point, keeping a legacy system as-is and repairing it with eBay-sourced parts is not an option. It is rarely possible to plug-and-play when exchanging hardware platforms. PLC coding means and methods were not standardized among manufacturers or systems integrators (SIs). This variability makes any migration, or upgrade for that matter, more difficult.
While an upgrade can be a clean-slate approach, it also involves an invasive rip-and-replace process with significant downtime, risk, and cost. Crucial existing functionality may be overlooked or misunderstood.
It is preferable in many cases to plan a more progressive migration, preserving a system’s control strategies to the greatest extent possible, while incorporating modest improvements where warranted.
Tools for Migrations
Most major PLC manufacturers offer specialized hardware and software migration tools to facilitate the process of transitioning legacy systems to modern systems. Hardware retrofit adapters enable new platforms to interconnect with existing field hardware and connections.
Software conversion tools are crucial for preserving as much logic as possible, although experienced programmers must still audit the code for unsupported functions, mismatched data types, and specific concerns such as peer-to-peer communications.
Tesco understands the processes and platforms involved, and it has a strong record of executing migration projects. The Tesco team is familiar with site investigations, holding workshops among all parties, and performing the detailed hardware and software design required to deliver a successful project.
Example 1: Rockwell Automation
One wastewater municipality wanted to upgrade their Allen-Bradley PLC-5 platforms to modern ControlLogix Ethernet-based systems, while preserving the existing FactoryTalk View SE supervisory control and data acquisition (SCADA) system. Tesco Controls leveraged Rockwell Automation’s conversion products and tools to efficiently migrate the existing hardware and software, performing a seamless hot cutover of the PLCs using good documentation practices, appropriate contingency plans and a thorough understanding of the plant’s operational characteristics and the end user’s goals.
Example 2: Schneider Electric
A water treatment plant used equipment and legacy automation platforms which were no longer supported by the OEM, so some sort of upgrade became necessary. After backing up all existing code, Tesco Controls performed an initial hardware/software migration, with only minimal downtime required for demolition and upgrade work. The work also included documenting the resultant code and combining the function of two PLCs into one.
Conclusion
The saying “nothing lasts forever” certainly applies to industrial automation systems.
When old automation systems finally require an upgrade, a balanced approach of migrating legacy industrial automation programs into new platforms can be the preferred solution. This approach provides the best method for preserving existing functionality while minimizing downtime.
Tesco Controls stands ready as a trusted automation partner to help the water/wastewater industry with any needs for completely new projects, rip-and-replace upgrades, or efficient migrations.
Tesco Controls Inc. is a certified member of the Control System Integrators Association (CSIA).
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