A filling machine control retrofit replaces the programmable logic controller (PLC), drives and operator interface on a filler whose mechanical parts remain in good condition. Rotary piston fillers, cup fillers, cappers and monoblocks are often built to run for decades. Their controls are usually the first part to become unsupportable, and when they fail, a mechanically sound machine stops.
The signs a filler’s controls are the weak point
Food manufacturers usually recognise the situation from a combination of signs:
- The PLC, drive or touchscreen is no longer sold, and spares come from second-hand sources at increasing prices
- Only one person, or an overseas supplier, can change the program
- The operator screen has failed, been replaced with a different model, or is held together with workarounds
- Intermittent faults that cannot be traced because the drawings no longer match the machine
- Changeovers rely on settings written on paper rather than stored recipes
Any one of these can be managed. Together they mean the line depends on a machine that cannot be reliably repaired if its controller fails. ABB’s research found that unplanned downtime costs a typical Australian industrial business about $349,000 per hour. Even at a fraction of that figure, a filler waiting for a used controller is expensive.
Why the controls age faster than the machine
Stainless frames, cams, pistons and valves are designed for long service and can be rebuilt. Electronics follow the manufacturers’ product cycles, typically measured in years rather than decades. Older fillers also use proprietary controllers, drives and touchscreens selected by the original equipment manufacturer (OEM), sometimes with programs that cannot be read or changed without the OEM’s tools.
What a filling machine control retrofit replaces
The retrofit replaces the electronics and keeps everything that touches the product.
How the retrofit is carried out
- 1
Capture
The existing program, settings, sequence timing and every fault message are recorded before anything is changed.
- 2
Rebuild
The control program is written on a current platform in IEC 61131-3 languages, reproducing the existing behaviour and documenting it fully.
- 3
Test off-site
The new panel and program are tested with simulated inputs for every product, recipe and fault condition.
- 4
Cut over
The new controls are installed during a planned shutdown, and the machine is run on each product before release to production.
Once a filler has current controls, closed-loop fill-weight control becomes a straightforward addition. The approach for liquid lines is described in sauce filling machine accuracy.
The commercial case
The case for a controls retrofit rests mainly on risk: the cost of an extended outage on a critical filler, weighed against a planned project at a fixed price. Secondary benefits include faster changeovers with stored recipes, quicker fault-finding with clear alarms, and a machine the site can support itself.
Alternatives
- Hold spares. Buying used controllers and drives buys time, but spares age on the shelf and do not solve documentation or programming access.
- A new filler. The right choice when the mechanics are worn. Where they are sound, a new machine costs far more and brings its own commissioning risk.
- The original manufacturer’s upgrade. Worth asking about, though older models are often no longer supported and the upgrade may still use proprietary components.
- A large systems integrator. Suited to whole-line projects. A single filler retrofit rarely justifies their overheads.