Machine Retrofitting: When to Upgrade an Old Machine Instead of Replacing It
By AB Automation Team3 min read
Many factories run machines that are mechanically sound but held back by their controls: obsolete PLCs nobody can program, relay logic full of patches, DC drives with no spares, or an HMI with a failing screen. Buying a new machine is expensive and means new foundations, training and commissioning. Machine retrofitting keeps the proven mechanics and replaces the control system with modern, supported components.
Signs your machine is a retrofit candidate
- The PLC, HMI or drives are discontinued and spares are scarce or expensive.
- Breakdowns are increasingly electrical, while the mechanics are still in good shape.
- Only one person in the plant (or nobody) understands the control logic.
- No backup of the program exists, so a single failure could stop the machine for weeks.
- You need features the old system cannot give: recipes, data logging, faster changeover, energy saving or remote support.
- Safety circuits no longer meet current expectations.
Retrofit or replace?
| Retrofit makes sense when | Replacement makes sense when |
|---|---|
| Frame, guides and mechanics are in good condition | Mechanics are worn out or inaccurate |
| The process and output are still right for your product | You need much higher capacity or a different process |
| Imported machine with no local support for its controls | Retrofit cost approaches the price of a new machine |
| Downtime must be limited and planned | The machine is near the end of its economic life anyway |
In our experience a controls retrofit typically costs a fraction of a new machine, though the figure varies widely with size and complexity.
What a typical retrofit includes
- Study of the existing system. We document the machine's sequence, decode old wiring and read whatever drawings and programs exist. Operators are interviewed, because they know the machine's quirks.
- Design. New PLC, HMI and drive selection, electrical drawings and a functional description agreed with you before work starts.
- Panel building. A new control panel is built and tested in our workshop, so the machine keeps running in the meantime.
- Programming and simulation. PLC and HMI programs are written and tested offline.
- Changeover. Old panel out, new panel in, field wiring connected and checked. With good preparation this can often be done over a planned shutdown.
- Commissioning and training. Trial runs, fine-tuning with production, documentation and operator/maintenance training.
Common retrofit upgrades
- Relay logic or old PLC to a Mitsubishi FX5U or iQ-R PLC
- Push-button panels or old text displays to a GOT2000 touch HMI
- DC drives and slip-ring motors to AC motors with VFDs
- Mechanical cams and clutches to servo-driven motion
- Pneumatic indexers to electric hollow rotary actuators
- Adding energy monitoring, production counters and alarm logging
Keeping downtime short
- Build and test the panel before the shutdown.
- Label every field wire before disconnecting the old panel.
- Keep the old panel intact (if possible) until the new system is proven.
- Plan commissioning with production so trial material and operators are available.
Talk to us about retrofitting your machine
AB Automation has more than 16 years of experience modernising textile, packaging, engineering and process machines across Gujarat and India. Learn more about our retrofitting and modernisation service, or send us photos of your machine and panel for an initial assessment.
Need help with your automation project?
Talk to AB Automation’s engineers — authorised Mitsubishi Electric partner & Oriental Motor distributor.