April 9, 2025

Modernising control systems: keeping Excel while embracing automation

Excel: a lifeline or a liability?

If you’ve spent any time in mineral processing, you’ve probably worked with Excel for process calculations. It’s flexible, familiar and gets the job done. But as plants push for more automation, integrating Excel into modern control systems can be a real headache.

A North American smelter recently found itself in this exact situation. For years, its copper-converting furnace relied on an Excel-based model to manage setpoints. The problem? The system was running on aging hardware with no path for upgrades. It needed a way to modernise – without losing the tools that had kept the process running for decades.

When full DCS integration isn’t the answer

The first thought was to move everything into the distributed control system (DCS), but that quickly hit roadblocks, for example:

Excel’s solver wasn’t compatible – The heat and mass balance calculations used Excel’s iterative solver, which simply wouldn’t work inside a DCS.
Too many complex equations – Rewriting them for the DCS would have taken months if not years, with extensive verification.
Database dependencies – The system needed to pull lab data in real time – something the DCS wasn’t built to handle.

Scrapping Excel altogether wasn’t an option. Instead, the challenge became: how do we keep what works while modernising the rest?

The smarter approach: hybrid integration

Rather than forcing everything into the DCS, the solution was a hybrid approach – one that embraced Excel’s strengths while eliminating manual processes and outdated infrastructure.

Here’s what changed:

Modern application, familiar interface
The entire application was migrated to a supported, web-based platform, ensuring long-term maintainability. But for the operators and metallurgists, the core workflow stayed the same—no steep learning curve, just a better system with an improved user interface.
Excel stays where it makes sense
Instead of replacing Excel, the smelter kept using it for critical calculations. Metallurgists could upload updated Excel files when needed, controlling revisions, maintaining flexibility while avoiding unnecessary software overhauls.
Automated setpoint transfers
Previously, operators had to manually enter suggested setpoints from Excel’s model into the DCS. That’s a slow, error-prone process. The new system now transfers setpoints automatically for operator acceptance, reducing risk and freeing up operator time.
Stronger data validation and security
To prevent bad data from creeping in, limits and validation checks were added to data entry fields. PI tags were also created to track trends and provide historical insights.

Big wins: what this means for operations

By modernising without overcomplicating, the smelter achieved:

Better reliability – The system now runs on supported infrastructure, reducing downtime risk.
More efficiency – Automating setpoint transfers eliminated manual inputs and operator errors.
Greater flexibility – Metallurgists can still tweak calculations as needed without IT/OT intervention or disrupting the operation.
Scalability – This bespoke software solution can be applied to other smelters or plants with similar process model challenges.

The future: smarter, not harder

Excel isn’t going anywhere anytime soon. While fully integrated model-based control systems offer powerful automation, Excel remains a go-to tool for engineers needing quick, adaptable calculations. The key is knowing when to integrate and when to automate.

For anyone running an old Excel-based process model to operate key equipment, this smelter’s experience proves that you don’t have to throw everything out to move forward. With the right approach, you can keep the tools that work while upgrading for a more automated future.

When modernising control systems, it isn’t about getting rid of Excel—it’s about making it work smarter.

Need to modernise your control system without losing the tools you rely on?

Mipac specialises in integrating new technologies while preserving the best of what already works. If your operation depends on Excel-based models and you’re looking for a way to future-proof your system, we can help. Get in touch to discuss how we can tailor a solution for your site.