Control System Retrofits
Modernizing legacy and obsolete control systems for industrial equipment in Ontario — obsolete PLC and drive replacement, HMI migration, and network upgrades, sequenced to avoid unplanned downtime.
Legacy Systems, Modernized Without Starting Over
Obsolete PLC & Drive Replacement
Migrating off discontinued controllers and drives before a failure forces the decision for you.
Legacy HMI Migration
Moving operator screens off unsupported platforms onto current hardware, without losing what operators already know.
Network & Communication Upgrades
Replacing legacy communication links with current, supportable network architecture.
I/O System Replacement
Swapping obsolete I/O hardware while keeping field wiring and device terminations intact wherever possible.
Reverse Engineering Undocumented Systems
No drawings for the existing system? We document what's actually there before changing any of it.
Documentation Update
As-built drawings and program files brought current, so the next person isn't troubleshooting blind.
Modernized on Your Timeline, Not a Forced Shutdown
Existing System Review
Drawings reviewed if they exist; logic and wiring reverse-engineered if they don't.
Risk & Scope Definition
Obsolete components, spare parts availability, and what can stay versus what has to change.
Migration Plan
Work sequenced to minimize disruption, often planned around an existing shutdown window.
Programming & Panel Work
New PLC and HMI programs developed and panel work completed, tested off-line wherever possible.
Cutover & Commissioning
Swap and validate against the original system, with a fallback plan if something doesn't go as expected.
As-Built Documentation
Drawings and program files updated to match exactly what's installed when the work is done.
Legacy Systems We've Modernized
- • OEM support for equipment has ended
- • Spare parts are no longer available for the existing system
- • System is causing unplanned downtime
- • Existing controls have no current drawings or documentation
Common Questions
Can you retrofit a system with no existing drawings?
Yes. Reverse engineering undocumented panels and logic is a routine first step before a retrofit — we document what's actually there before changing anything.
How do you minimize downtime during a retrofit?
Work is sequenced around your existing shutdown windows, with programming and panel work completed and tested off-line wherever possible before cutover.
Do you replace just the PLC, or the whole panel?
Depends on scope. Sometimes it's a straight PLC or drive swap; sometimes the panel itself is obsolete and needs a full rebuild. We scope it to what's actually needed.
Can you migrate an old HMI without changing the PLC?
Yes, when the PLC platform still has a path forward. HMI and PLC migrations are scoped together but don't always have to happen at the same time.
What if spare parts for our existing system are no longer available?
That's one of the most common reasons we get called in. We'll help you decide whether to source legacy parts as a stopgap or move forward with a retrofit.
Ready to Discuss Your Project?
We work with plant managers, OEMs, and integrators across Ontario. Let's talk about what you need.
+1 (905) 960-9535company@gohncontrols.comSend Us a Message