Background
Mackay Sugar’s Racecourse Mill had been running three PLC-5 systems controlling primary mill drive sequencing since the mid-2000s. Spare parts availability had become critical and one system had already suffered an unplanned failure mid-crush the previous season.
What we did
The migration covered approximately 1,400 I/O points across three control panels. We ran a full shadow program during the final weeks of the previous crush season — logging live signal states to validate our logic before we ever touched the hardware.
The physical cutover was a single-panel-at-a-time swap with immediate I/O verification at each stage, using a structured commissioning checklist signed off by the mill’s own electricians at each hold point.
Result
The mill started the following crush season with no PLC-related stoppages. The site now has a single programming environment across all drive controls, and the maintenance team can modify sequences without engaging an external contractor for every change.